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a362032e | 1 | .. SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | |
a362032e MCC |
3 | =================================== |
4 | Linux Ethernet Bonding Driver HOWTO | |
5 | =================================== | |
00354cfb | 6 | |
a362032e MCC |
7 | Latest update: 27 April 2011 |
8 | ||
9 | Initial release: Thomas Davis <tadavis at lbl.gov> | |
10 | ||
11 | Corrections, HA extensions: 2000/10/03-15: | |
1da177e4 | 12 | |
1da177e4 LT |
13 | - Willy Tarreau <willy at meta-x.org> |
14 | - Constantine Gavrilov <const-g at xpert.com> | |
15 | - Chad N. Tindel <ctindel at ieee dot org> | |
16 | - Janice Girouard <girouard at us dot ibm dot com> | |
17 | - Jay Vosburgh <fubar at us dot ibm dot com> | |
18 | ||
19 | Reorganized and updated Feb 2005 by Jay Vosburgh | |
6224e01d | 20 | Added Sysfs information: 2006/04/24 |
a362032e | 21 | |
6224e01d | 22 | - Mitch Williams <mitch.a.williams at intel.com> |
1da177e4 | 23 | |
00354cfb JV |
24 | Introduction |
25 | ============ | |
26 | ||
a362032e | 27 | The Linux bonding driver provides a method for aggregating |
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28 | multiple network interfaces into a single logical "bonded" interface. |
29 | The behavior of the bonded interfaces depends upon the mode; generally | |
30 | speaking, modes provide either hot standby or load balancing services. | |
31 | Additionally, link integrity monitoring may be performed. | |
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32 | |
33 | The bonding driver originally came from Donald Becker's | |
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34 | beowulf patches for kernel 2.0. It has changed quite a bit since, and |
35 | the original tools from extreme-linux and beowulf sites will not work | |
36 | with this version of the driver. | |
1da177e4 | 37 | |
a362032e | 38 | For new versions of the driver, updated userspace tools, and |
00354cfb | 39 | who to ask for help, please follow the links at the end of this file. |
1da177e4 | 40 | |
a362032e | 41 | .. Table of Contents |
1da177e4 | 42 | |
a362032e | 43 | 1. Bonding Driver Installation |
1da177e4 | 44 | |
a362032e | 45 | 2. Bonding Driver Options |
1da177e4 | 46 | |
a362032e MCC |
47 | 3. Configuring Bonding Devices |
48 | 3.1 Configuration with Sysconfig Support | |
49 | 3.1.1 Using DHCP with Sysconfig | |
50 | 3.1.2 Configuring Multiple Bonds with Sysconfig | |
51 | 3.2 Configuration with Initscripts Support | |
52 | 3.2.1 Using DHCP with Initscripts | |
53 | 3.2.2 Configuring Multiple Bonds with Initscripts | |
54 | 3.3 Configuring Bonding Manually with Ifenslave | |
55 | 3.3.1 Configuring Multiple Bonds Manually | |
56 | 3.4 Configuring Bonding Manually via Sysfs | |
57 | 3.5 Configuration with Interfaces Support | |
58 | 3.6 Overriding Configuration for Special Cases | |
59 | 3.7 Configuring LACP for 802.3ad mode in a more secure way | |
1da177e4 | 60 | |
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61 | 4. Querying Bonding Configuration |
62 | 4.1 Bonding Configuration | |
63 | 4.2 Network Configuration | |
1da177e4 | 64 | |
a362032e | 65 | 5. Switch Configuration |
1da177e4 | 66 | |
a362032e | 67 | 6. 802.1q VLAN Support |
1da177e4 | 68 | |
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69 | 7. Link Monitoring |
70 | 7.1 ARP Monitor Operation | |
71 | 7.2 Configuring Multiple ARP Targets | |
72 | 7.3 MII Monitor Operation | |
1da177e4 | 73 | |
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74 | 8. Potential Trouble Sources |
75 | 8.1 Adventures in Routing | |
76 | 8.2 Ethernet Device Renaming | |
77 | 8.3 Painfully Slow Or No Failed Link Detection By Miimon | |
1da177e4 | 78 | |
a362032e | 79 | 9. SNMP agents |
1da177e4 | 80 | |
a362032e | 81 | 10. Promiscuous mode |
1da177e4 | 82 | |
a362032e MCC |
83 | 11. Configuring Bonding for High Availability |
84 | 11.1 High Availability in a Single Switch Topology | |
85 | 11.2 High Availability in a Multiple Switch Topology | |
86 | 11.2.1 HA Bonding Mode Selection for Multiple Switch Topology | |
87 | 11.2.2 HA Link Monitoring for Multiple Switch Topology | |
00354cfb | 88 | |
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89 | 12. Configuring Bonding for Maximum Throughput |
90 | 12.1 Maximum Throughput in a Single Switch Topology | |
91 | 12.1.1 MT Bonding Mode Selection for Single Switch Topology | |
92 | 12.1.2 MT Link Monitoring for Single Switch Topology | |
93 | 12.2 Maximum Throughput in a Multiple Switch Topology | |
94 | 12.2.1 MT Bonding Mode Selection for Multiple Switch Topology | |
95 | 12.2.2 MT Link Monitoring for Multiple Switch Topology | |
1da177e4 | 96 | |
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97 | 13. Switch Behavior Issues |
98 | 13.1 Link Establishment and Failover Delays | |
99 | 13.2 Duplicated Incoming Packets | |
1da177e4 | 100 | |
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101 | 14. Hardware Specific Considerations |
102 | 14.1 IBM BladeCenter | |
1da177e4 | 103 | |
a362032e | 104 | 15. Frequently Asked Questions |
00354cfb | 105 | |
a362032e | 106 | 16. Resources and Links |
1da177e4 LT |
107 | |
108 | ||
109 | 1. Bonding Driver Installation | |
110 | ============================== | |
111 | ||
a362032e | 112 | Most popular distro kernels ship with the bonding driver |
b1098bbe | 113 | already available as a module. If your distro does not, or you |
1da177e4 LT |
114 | have need to compile bonding from source (e.g., configuring and |
115 | installing a mainline kernel from kernel.org), you'll need to perform | |
116 | the following steps: | |
117 | ||
118 | 1.1 Configure and build the kernel with bonding | |
119 | ----------------------------------------------- | |
120 | ||
a362032e | 121 | The current version of the bonding driver is available in the |
1da177e4 | 122 | drivers/net/bonding subdirectory of the most recent kernel source |
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123 | (which is available on http://kernel.org). Most users "rolling their |
124 | own" will want to use the most recent kernel from kernel.org. | |
1da177e4 | 125 | |
a362032e | 126 | Configure kernel with "make menuconfig" (or "make xconfig" or |
1da177e4 LT |
127 | "make config"), then select "Bonding driver support" in the "Network |
128 | device support" section. It is recommended that you configure the | |
129 | driver as module since it is currently the only way to pass parameters | |
130 | to the driver or configure more than one bonding device. | |
131 | ||
a362032e | 132 | Build and install the new kernel and modules. |
1da177e4 | 133 | |
b1098bbe | 134 | 1.2 Bonding Control Utility |
a362032e | 135 | --------------------------- |
1da177e4 | 136 | |
a362032e | 137 | It is recommended to configure bonding via iproute2 (netlink) |
b1098bbe | 138 | or sysfs, the old ifenslave control utility is obsolete. |
1da177e4 LT |
139 | |
140 | 2. Bonding Driver Options | |
141 | ========================= | |
142 | ||
a362032e | 143 | Options for the bonding driver are supplied as parameters to the |
9a6c6867 JV |
144 | bonding module at load time, or are specified via sysfs. |
145 | ||
a362032e | 146 | Module options may be given as command line arguments to the |
9a6c6867 | 147 | insmod or modprobe command, but are usually specified in either the |
a362032e | 148 | ``/etc/modprobe.d/*.conf`` configuration files, or in a distro-specific |
970e2486 | 149 | configuration file (some of which are detailed in the next section). |
9a6c6867 | 150 | |
a362032e | 151 | Details on bonding support for sysfs is provided in the |
9a6c6867 | 152 | "Configuring Bonding Manually via Sysfs" section, below. |
1da177e4 | 153 | |
a362032e | 154 | The available bonding driver parameters are listed below. If a |
1da177e4 LT |
155 | parameter is not specified the default value is used. When initially |
156 | configuring a bond, it is recommended "tail -f /var/log/messages" be | |
157 | run in a separate window to watch for bonding driver error messages. | |
158 | ||
a362032e | 159 | It is critical that either the miimon or arp_interval and |
1da177e4 LT |
160 | arp_ip_target parameters be specified, otherwise serious network |
161 | degradation will occur during link failures. Very few devices do not | |
162 | support at least miimon, so there is really no reason not to use it. | |
163 | ||
a362032e | 164 | Options with textual values will accept either the text name |
00354cfb JV |
165 | or, for backwards compatibility, the option value. E.g., |
166 | "mode=802.3ad" and "mode=4" set the same mode. | |
1da177e4 | 167 | |
a362032e | 168 | The parameters are as follows: |
1da177e4 | 169 | |
1ba9ac7c NP |
170 | active_slave |
171 | ||
172 | Specifies the new active slave for modes that support it | |
173 | (active-backup, balance-alb and balance-tlb). Possible values | |
174 | are the name of any currently enslaved interface, or an empty | |
175 | string. If a name is given, the slave and its link must be up in order | |
176 | to be selected as the new active slave. If an empty string is | |
177 | specified, the current active slave is cleared, and a new active | |
178 | slave is selected automatically. | |
179 | ||
180 | Note that this is only available through the sysfs interface. No module | |
181 | parameter by this name exists. | |
182 | ||
183 | The normal value of this option is the name of the currently | |
184 | active slave, or the empty string if there is no active slave or | |
185 | the current mode does not use an active slave. | |
186 | ||
6791e466 MB |
187 | ad_actor_sys_prio |
188 | ||
189 | In an AD system, this specifies the system priority. The allowed range | |
190 | is 1 - 65535. If the value is not specified, it takes 65535 as the | |
191 | default value. | |
192 | ||
193 | This parameter has effect only in 802.3ad mode and is available through | |
194 | SysFs interface. | |
195 | ||
74514957 MB |
196 | ad_actor_system |
197 | ||
198 | In an AD system, this specifies the mac-address for the actor in | |
1c15b05b FFM |
199 | protocol packet exchanges (LACPDUs). The value cannot be a multicast |
200 | address. If the all-zeroes MAC is specified, bonding will internally | |
201 | use the MAC of the bond itself. It is preferred to have the | |
202 | local-admin bit set for this mac but driver does not enforce it. If | |
203 | the value is not given then system defaults to using the masters' | |
204 | mac address as actors' system address. | |
74514957 MB |
205 | |
206 | This parameter has effect only in 802.3ad mode and is available through | |
207 | SysFs interface. | |
208 | ||
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209 | ad_select |
210 | ||
211 | Specifies the 802.3ad aggregation selection logic to use. The | |
212 | possible values and their effects are: | |
213 | ||
214 | stable or 0 | |
215 | ||
216 | The active aggregator is chosen by largest aggregate | |
217 | bandwidth. | |
218 | ||
219 | Reselection of the active aggregator occurs only when all | |
220 | slaves of the active aggregator are down or the active | |
221 | aggregator has no slaves. | |
222 | ||
223 | This is the default value. | |
224 | ||
225 | bandwidth or 1 | |
226 | ||
227 | The active aggregator is chosen by largest aggregate | |
228 | bandwidth. Reselection occurs if: | |
229 | ||
230 | - A slave is added to or removed from the bond | |
231 | ||
232 | - Any slave's link state changes | |
233 | ||
234 | - Any slave's 802.3ad association state changes | |
235 | ||
19f59460 | 236 | - The bond's administrative state changes to up |
fd989c83 JV |
237 | |
238 | count or 2 | |
239 | ||
240 | The active aggregator is chosen by the largest number of | |
241 | ports (slaves). Reselection occurs as described under the | |
242 | "bandwidth" setting, above. | |
243 | ||
244 | The bandwidth and count selection policies permit failover of | |
245 | 802.3ad aggregations when partial failure of the active aggregator | |
246 | occurs. This keeps the aggregator with the highest availability | |
247 | (either in bandwidth or in number of ports) active at all times. | |
248 | ||
249 | This option was added in bonding version 3.4.0. | |
250 | ||
d22a5fc0 MB |
251 | ad_user_port_key |
252 | ||
253 | In an AD system, the port-key has three parts as shown below - | |
254 | ||
a362032e | 255 | ===== ============ |
d22a5fc0 | 256 | Bits Use |
a362032e | 257 | ===== ============ |
d22a5fc0 MB |
258 | 00 Duplex |
259 | 01-05 Speed | |
260 | 06-15 User-defined | |
a362032e | 261 | ===== ============ |
d22a5fc0 MB |
262 | |
263 | This defines the upper 10 bits of the port key. The values can be | |
264 | from 0 - 1023. If not given, the system defaults to 0. | |
265 | ||
266 | This parameter has effect only in 802.3ad mode and is available through | |
267 | SysFs interface. | |
268 | ||
025890b4 NP |
269 | all_slaves_active |
270 | ||
271 | Specifies that duplicate frames (received on inactive ports) should be | |
272 | dropped (0) or delivered (1). | |
273 | ||
274 | Normally, bonding will drop duplicate frames (received on inactive | |
275 | ports), which is desirable for most users. But there are some times | |
276 | it is nice to allow duplicate frames to be delivered. | |
277 | ||
278 | The default value is 0 (drop duplicate frames received on inactive | |
279 | ports). | |
280 | ||
1da177e4 LT |
281 | arp_interval |
282 | ||
00354cfb | 283 | Specifies the ARP link monitoring frequency in milliseconds. |
f5b2b966 JV |
284 | |
285 | The ARP monitor works by periodically checking the slave | |
286 | devices to determine whether they have sent or received | |
287 | traffic recently (the precise criteria depends upon the | |
288 | bonding mode, and the state of the slave). Regular traffic is | |
289 | generated via ARP probes issued for the addresses specified by | |
290 | the arp_ip_target option. | |
291 | ||
292 | This behavior can be modified by the arp_validate option, | |
293 | below. | |
294 | ||
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295 | If ARP monitoring is used in an etherchannel compatible mode |
296 | (modes 0 and 2), the switch should be configured in a mode | |
297 | that evenly distributes packets across all links. If the | |
298 | switch is configured to distribute the packets in an XOR | |
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299 | fashion, all replies from the ARP targets will be received on |
300 | the same link which could cause the other team members to | |
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301 | fail. ARP monitoring should not be used in conjunction with |
302 | miimon. A value of 0 disables ARP monitoring. The default | |
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303 | value is 0. |
304 | ||
305 | arp_ip_target | |
306 | ||
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307 | Specifies the IP addresses to use as ARP monitoring peers when |
308 | arp_interval is > 0. These are the targets of the ARP request | |
309 | sent to determine the health of the link to the targets. | |
310 | Specify these values in ddd.ddd.ddd.ddd format. Multiple IP | |
311 | addresses must be separated by a comma. At least one IP | |
312 | address must be given for ARP monitoring to function. The | |
313 | maximum number of targets that can be specified is 16. The | |
314 | default value is no IP addresses. | |
1da177e4 | 315 | |
129e3c1b HL |
316 | ns_ip6_target |
317 | ||
318 | Specifies the IPv6 addresses to use as IPv6 monitoring peers when | |
319 | arp_interval is > 0. These are the targets of the NS request | |
320 | sent to determine the health of the link to the targets. | |
321 | Specify these values in ffff:ffff::ffff:ffff format. Multiple IPv6 | |
322 | addresses must be separated by a comma. At least one IPv6 | |
323 | address must be given for NS/NA monitoring to function. The | |
324 | maximum number of targets that can be specified is 16. The | |
325 | default value is no IPv6 addresses. | |
326 | ||
f5b2b966 JV |
327 | arp_validate |
328 | ||
329 | Specifies whether or not ARP probes and replies should be | |
52f65ef3 VF |
330 | validated in any mode that supports arp monitoring, or whether |
331 | non-ARP traffic should be filtered (disregarded) for link | |
332 | monitoring purposes. | |
f5b2b966 JV |
333 | |
334 | Possible values are: | |
335 | ||
336 | none or 0 | |
337 | ||
52f65ef3 | 338 | No validation or filtering is performed. |
f5b2b966 JV |
339 | |
340 | active or 1 | |
341 | ||
342 | Validation is performed only for the active slave. | |
343 | ||
344 | backup or 2 | |
345 | ||
346 | Validation is performed only for backup slaves. | |
347 | ||
348 | all or 3 | |
349 | ||
350 | Validation is performed for all slaves. | |
351 | ||
52f65ef3 VF |
352 | filter or 4 |
353 | ||
354 | Filtering is applied to all slaves. No validation is | |
355 | performed. | |
356 | ||
357 | filter_active or 5 | |
358 | ||
359 | Filtering is applied to all slaves, validation is performed | |
360 | only for the active slave. | |
361 | ||
362 | filter_backup or 6 | |
363 | ||
364 | Filtering is applied to all slaves, validation is performed | |
365 | only for backup slaves. | |
366 | ||
367 | Validation: | |
368 | ||
369 | Enabling validation causes the ARP monitor to examine the incoming | |
370 | ARP requests and replies, and only consider a slave to be up if it | |
371 | is receiving the appropriate ARP traffic. | |
372 | ||
373 | For an active slave, the validation checks ARP replies to confirm | |
374 | that they were generated by an arp_ip_target. Since backup slaves | |
375 | do not typically receive these replies, the validation performed | |
376 | for backup slaves is on the broadcast ARP request sent out via the | |
377 | active slave. It is possible that some switch or network | |
378 | configurations may result in situations wherein the backup slaves | |
379 | do not receive the ARP requests; in such a situation, validation | |
380 | of backup slaves must be disabled. | |
381 | ||
382 | The validation of ARP requests on backup slaves is mainly helping | |
383 | bonding to decide which slaves are more likely to work in case of | |
384 | the active slave failure, it doesn't really guarantee that the | |
385 | backup slave will work if it's selected as the next active slave. | |
386 | ||
387 | Validation is useful in network configurations in which multiple | |
388 | bonding hosts are concurrently issuing ARPs to one or more targets | |
389 | beyond a common switch. Should the link between the switch and | |
390 | target fail (but not the switch itself), the probe traffic | |
391 | generated by the multiple bonding instances will fool the standard | |
392 | ARP monitor into considering the links as still up. Use of | |
393 | validation can resolve this, as the ARP monitor will only consider | |
394 | ARP requests and replies associated with its own instance of | |
395 | bonding. | |
396 | ||
397 | Filtering: | |
398 | ||
399 | Enabling filtering causes the ARP monitor to only use incoming ARP | |
400 | packets for link availability purposes. Arriving packets that are | |
401 | not ARPs are delivered normally, but do not count when determining | |
402 | if a slave is available. | |
403 | ||
404 | Filtering operates by only considering the reception of ARP | |
405 | packets (any ARP packet, regardless of source or destination) when | |
406 | determining if a slave has received traffic for link availability | |
407 | purposes. | |
408 | ||
409 | Filtering is useful in network configurations in which significant | |
410 | levels of third party broadcast traffic would fool the standard | |
411 | ARP monitor into considering the links as still up. Use of | |
412 | filtering can resolve this, as only ARP traffic is considered for | |
413 | link availability purposes. | |
f5b2b966 JV |
414 | |
415 | This option was added in bonding version 3.1.0. | |
416 | ||
8599b52e VF |
417 | arp_all_targets |
418 | ||
419 | Specifies the quantity of arp_ip_targets that must be reachable | |
420 | in order for the ARP monitor to consider a slave as being up. | |
421 | This option affects only active-backup mode for slaves with | |
422 | arp_validation enabled. | |
423 | ||
424 | Possible values are: | |
425 | ||
426 | any or 0 | |
427 | ||
428 | consider the slave up only when any of the arp_ip_targets | |
429 | is reachable | |
430 | ||
431 | all or 1 | |
432 | ||
433 | consider the slave up only when all of the arp_ip_targets | |
434 | are reachable | |
435 | ||
5944b5ab HL |
436 | arp_missed_max |
437 | ||
438 | Specifies the number of arp_interval monitor checks that must | |
439 | fail in order for an interface to be marked down by the ARP monitor. | |
440 | ||
441 | In order to provide orderly failover semantics, backup interfaces | |
442 | are permitted an extra monitor check (i.e., they must fail | |
443 | arp_missed_max + 1 times before being marked down). | |
444 | ||
445 | The default value is 2, and the allowable range is 1 - 255. | |
446 | ||
1da177e4 LT |
447 | downdelay |
448 | ||
449 | Specifies the time, in milliseconds, to wait before disabling | |
450 | a slave after a link failure has been detected. This option | |
451 | is only valid for the miimon link monitor. The downdelay | |
452 | value should be a multiple of the miimon value; if not, it | |
453 | will be rounded down to the nearest multiple. The default | |
454 | value is 0. | |
455 | ||
dd957c57 JV |
456 | fail_over_mac |
457 | ||
458 | Specifies whether active-backup mode should set all slaves to | |
3915c1e8 JV |
459 | the same MAC address at enslavement (the traditional |
460 | behavior), or, when enabled, perform special handling of the | |
461 | bond's MAC address in accordance with the selected policy. | |
462 | ||
463 | Possible values are: | |
464 | ||
465 | none or 0 | |
466 | ||
467 | This setting disables fail_over_mac, and causes | |
468 | bonding to set all slaves of an active-backup bond to | |
469 | the same MAC address at enslavement time. This is the | |
470 | default. | |
471 | ||
472 | active or 1 | |
473 | ||
474 | The "active" fail_over_mac policy indicates that the | |
475 | MAC address of the bond should always be the MAC | |
476 | address of the currently active slave. The MAC | |
477 | address of the slaves is not changed; instead, the MAC | |
478 | address of the bond changes during a failover. | |
479 | ||
480 | This policy is useful for devices that cannot ever | |
481 | alter their MAC address, or for devices that refuse | |
482 | incoming broadcasts with their own source MAC (which | |
483 | interferes with the ARP monitor). | |
484 | ||
485 | The down side of this policy is that every device on | |
486 | the network must be updated via gratuitous ARP, | |
487 | vs. just updating a switch or set of switches (which | |
488 | often takes place for any traffic, not just ARP | |
489 | traffic, if the switch snoops incoming traffic to | |
490 | update its tables) for the traditional method. If the | |
491 | gratuitous ARP is lost, communication may be | |
492 | disrupted. | |
493 | ||
25985edc | 494 | When this policy is used in conjunction with the mii |
3915c1e8 JV |
495 | monitor, devices which assert link up prior to being |
496 | able to actually transmit and receive are particularly | |
19f59460 | 497 | susceptible to loss of the gratuitous ARP, and an |
3915c1e8 JV |
498 | appropriate updelay setting may be required. |
499 | ||
500 | follow or 2 | |
501 | ||
502 | The "follow" fail_over_mac policy causes the MAC | |
503 | address of the bond to be selected normally (normally | |
504 | the MAC address of the first slave added to the bond). | |
505 | However, the second and subsequent slaves are not set | |
506 | to this MAC address while they are in a backup role; a | |
507 | slave is programmed with the bond's MAC address at | |
508 | failover time (and the formerly active slave receives | |
509 | the newly active slave's MAC address). | |
510 | ||
511 | This policy is useful for multiport devices that | |
512 | either become confused or incur a performance penalty | |
513 | when multiple ports are programmed with the same MAC | |
514 | address. | |
515 | ||
516 | ||
517 | The default policy is none, unless the first slave cannot | |
518 | change its MAC address, in which case the active policy is | |
519 | selected by default. | |
520 | ||
521 | This option may be modified via sysfs only when no slaves are | |
522 | present in the bond. | |
523 | ||
524 | This option was added in bonding version 3.2.0. The "follow" | |
525 | policy was added in bonding version 3.3.0. | |
dd957c57 | 526 | |
3a755cd8 HL |
527 | lacp_active |
528 | Option specifying whether to send LACPDU frames periodically. | |
529 | ||
530 | off or 0 | |
531 | LACPDU frames acts as "speak when spoken to". | |
532 | ||
533 | on or 1 | |
534 | LACPDU frames are sent along the configured links | |
535 | periodically. See lacp_rate for more details. | |
536 | ||
537 | The default is on. | |
538 | ||
1da177e4 LT |
539 | lacp_rate |
540 | ||
541 | Option specifying the rate in which we'll ask our link partner | |
542 | to transmit LACPDU packets in 802.3ad mode. Possible values | |
543 | are: | |
544 | ||
545 | slow or 0 | |
00354cfb | 546 | Request partner to transmit LACPDUs every 30 seconds |
1da177e4 LT |
547 | |
548 | fast or 1 | |
549 | Request partner to transmit LACPDUs every 1 second | |
550 | ||
00354cfb JV |
551 | The default is slow. |
552 | ||
1da177e4 LT |
553 | max_bonds |
554 | ||
555 | Specifies the number of bonding devices to create for this | |
556 | instance of the bonding driver. E.g., if max_bonds is 3, and | |
557 | the bonding driver is not already loaded, then bond0, bond1 | |
b8a9787e JV |
558 | and bond2 will be created. The default value is 1. Specifying |
559 | a value of 0 will load bonding, but will not create any devices. | |
1da177e4 LT |
560 | |
561 | miimon | |
562 | ||
00354cfb JV |
563 | Specifies the MII link monitoring frequency in milliseconds. |
564 | This determines how often the link state of each slave is | |
565 | inspected for link failures. A value of zero disables MII | |
566 | link monitoring. A value of 100 is a good starting point. | |
567 | The use_carrier option, below, affects how the link state is | |
1da177e4 | 568 | determined. See the High Availability section for additional |
f036b97d JT |
569 | information. The default value is 100 if arp_interval is not |
570 | set. | |
1da177e4 | 571 | |
025890b4 NP |
572 | min_links |
573 | ||
574 | Specifies the minimum number of links that must be active before | |
575 | asserting carrier. It is similar to the Cisco EtherChannel min-links | |
576 | feature. This allows setting the minimum number of member ports that | |
577 | must be up (link-up state) before marking the bond device as up | |
578 | (carrier on). This is useful for situations where higher level services | |
579 | such as clustering want to ensure a minimum number of low bandwidth | |
580 | links are active before switchover. This option only affect 802.3ad | |
581 | mode. | |
582 | ||
583 | The default value is 0. This will cause carrier to be asserted (for | |
584 | 802.3ad mode) whenever there is an active aggregator, regardless of the | |
585 | number of available links in that aggregator. Note that, because an | |
586 | aggregator cannot be active without at least one available link, | |
587 | setting this option to 0 or to 1 has the exact same effect. | |
588 | ||
1da177e4 LT |
589 | mode |
590 | ||
591 | Specifies one of the bonding policies. The default is | |
592 | balance-rr (round robin). Possible values are: | |
593 | ||
594 | balance-rr or 0 | |
595 | ||
596 | Round-robin policy: Transmit packets in sequential | |
597 | order from the first available slave through the | |
598 | last. This mode provides load balancing and fault | |
599 | tolerance. | |
600 | ||
601 | active-backup or 1 | |
602 | ||
603 | Active-backup policy: Only one slave in the bond is | |
604 | active. A different slave becomes active if, and only | |
605 | if, the active slave fails. The bond's MAC address is | |
606 | externally visible on only one port (network adapter) | |
00354cfb JV |
607 | to avoid confusing the switch. |
608 | ||
609 | In bonding version 2.6.2 or later, when a failover | |
610 | occurs in active-backup mode, bonding will issue one | |
611 | or more gratuitous ARPs on the newly active slave. | |
6224e01d | 612 | One gratuitous ARP is issued for the bonding master |
00354cfb JV |
613 | interface and each VLAN interfaces configured above |
614 | it, provided that the interface has at least one IP | |
615 | address configured. Gratuitous ARPs issued for VLAN | |
616 | interfaces are tagged with the appropriate VLAN id. | |
617 | ||
618 | This mode provides fault tolerance. The primary | |
619 | option, documented below, affects the behavior of this | |
620 | mode. | |
1da177e4 LT |
621 | |
622 | balance-xor or 2 | |
623 | ||
00354cfb JV |
624 | XOR policy: Transmit based on the selected transmit |
625 | hash policy. The default policy is a simple [(source | |
92abf750 JX |
626 | MAC address XOR'd with destination MAC address XOR |
627 | packet type ID) modulo slave count]. Alternate transmit | |
628 | policies may be selected via the xmit_hash_policy option, | |
629 | described below. | |
00354cfb JV |
630 | |
631 | This mode provides load balancing and fault tolerance. | |
1da177e4 LT |
632 | |
633 | broadcast or 3 | |
634 | ||
635 | Broadcast policy: transmits everything on all slave | |
636 | interfaces. This mode provides fault tolerance. | |
637 | ||
638 | 802.3ad or 4 | |
639 | ||
640 | IEEE 802.3ad Dynamic link aggregation. Creates | |
641 | aggregation groups that share the same speed and | |
642 | duplex settings. Utilizes all slaves in the active | |
643 | aggregator according to the 802.3ad specification. | |
644 | ||
00354cfb JV |
645 | Slave selection for outgoing traffic is done according |
646 | to the transmit hash policy, which may be changed from | |
647 | the default simple XOR policy via the xmit_hash_policy | |
648 | option, documented below. Note that not all transmit | |
649 | policies may be 802.3ad compliant, particularly in | |
650 | regards to the packet mis-ordering requirements of | |
651 | section 43.2.4 of the 802.3ad standard. Differing | |
652 | peer implementations will have varying tolerances for | |
653 | noncompliance. | |
654 | ||
655 | Prerequisites: | |
1da177e4 LT |
656 | |
657 | 1. Ethtool support in the base drivers for retrieving | |
658 | the speed and duplex of each slave. | |
659 | ||
660 | 2. A switch that supports IEEE 802.3ad Dynamic link | |
661 | aggregation. | |
662 | ||
663 | Most switches will require some type of configuration | |
664 | to enable 802.3ad mode. | |
665 | ||
666 | balance-tlb or 5 | |
667 | ||
668 | Adaptive transmit load balancing: channel bonding that | |
e9f0fb88 MB |
669 | does not require any special switch support. |
670 | ||
671 | In tlb_dynamic_lb=1 mode; the outgoing traffic is | |
672 | distributed according to the current load (computed | |
673 | relative to the speed) on each slave. | |
674 | ||
675 | In tlb_dynamic_lb=0 mode; the load balancing based on | |
676 | current load is disabled and the load is distributed | |
677 | only using the hash distribution. | |
678 | ||
679 | Incoming traffic is received by the current slave. | |
680 | If the receiving slave fails, another slave takes over | |
681 | the MAC address of the failed receiving slave. | |
1da177e4 LT |
682 | |
683 | Prerequisite: | |
684 | ||
685 | Ethtool support in the base drivers for retrieving the | |
686 | speed of each slave. | |
687 | ||
688 | balance-alb or 6 | |
689 | ||
690 | Adaptive load balancing: includes balance-tlb plus | |
691 | receive load balancing (rlb) for IPV4 traffic, and | |
692 | does not require any special switch support. The | |
693 | receive load balancing is achieved by ARP negotiation. | |
694 | The bonding driver intercepts the ARP Replies sent by | |
695 | the local system on their way out and overwrites the | |
696 | source hardware address with the unique hardware | |
697 | address of one of the slaves in the bond such that | |
698 | different peers use different hardware addresses for | |
699 | the server. | |
700 | ||
701 | Receive traffic from connections created by the server | |
702 | is also balanced. When the local system sends an ARP | |
703 | Request the bonding driver copies and saves the peer's | |
704 | IP information from the ARP packet. When the ARP | |
705 | Reply arrives from the peer, its hardware address is | |
706 | retrieved and the bonding driver initiates an ARP | |
707 | reply to this peer assigning it to one of the slaves | |
708 | in the bond. A problematic outcome of using ARP | |
709 | negotiation for balancing is that each time that an | |
710 | ARP request is broadcast it uses the hardware address | |
711 | of the bond. Hence, peers learn the hardware address | |
712 | of the bond and the balancing of receive traffic | |
713 | collapses to the current slave. This is handled by | |
714 | sending updates (ARP Replies) to all the peers with | |
715 | their individually assigned hardware address such that | |
716 | the traffic is redistributed. Receive traffic is also | |
717 | redistributed when a new slave is added to the bond | |
718 | and when an inactive slave is re-activated. The | |
719 | receive load is distributed sequentially (round robin) | |
720 | among the group of highest speed slaves in the bond. | |
721 | ||
722 | When a link is reconnected or a new slave joins the | |
723 | bond the receive traffic is redistributed among all | |
00354cfb | 724 | active slaves in the bond by initiating ARP Replies |
6224e01d | 725 | with the selected MAC address to each of the |
1da177e4 LT |
726 | clients. The updelay parameter (detailed below) must |
727 | be set to a value equal or greater than the switch's | |
728 | forwarding delay so that the ARP Replies sent to the | |
729 | peers will not be blocked by the switch. | |
730 | ||
731 | Prerequisites: | |
732 | ||
733 | 1. Ethtool support in the base drivers for retrieving | |
734 | the speed of each slave. | |
735 | ||
736 | 2. Base driver support for setting the hardware | |
737 | address of a device while it is open. This is | |
738 | required so that there will always be one slave in the | |
739 | team using the bond hardware address (the | |
740 | curr_active_slave) while having a unique hardware | |
741 | address for each slave in the bond. If the | |
742 | curr_active_slave fails its hardware address is | |
743 | swapped with the new curr_active_slave that was | |
744 | chosen. | |
745 | ||
a362032e | 746 | num_grat_arp, |
305d552a BH |
747 | num_unsol_na |
748 | ||
ad246c99 BH |
749 | Specify the number of peer notifications (gratuitous ARPs and |
750 | unsolicited IPv6 Neighbor Advertisements) to be issued after a | |
751 | failover event. As soon as the link is up on the new slave | |
752 | (possibly immediately) a peer notification is sent on the | |
0307d589 VB |
753 | bonding device and each VLAN sub-device. This is repeated at |
754 | the rate specified by peer_notif_delay if the number is | |
755 | greater than 1. | |
ad246c99 BH |
756 | |
757 | The valid range is 0 - 255; the default value is 1. These options | |
758 | affect only the active-backup mode. These options were added for | |
759 | bonding versions 3.3.0 and 3.4.0 respectively. | |
760 | ||
8fb4e139 | 761 | From Linux 3.0 and bonding version 3.7.1, these notifications |
ad246c99 BH |
762 | are generated by the ipv4 and ipv6 code and the numbers of |
763 | repetitions cannot be set independently. | |
305d552a | 764 | |
12465fb8 NA |
765 | packets_per_slave |
766 | ||
767 | Specify the number of packets to transmit through a slave before | |
768 | moving to the next one. When set to 0 then a slave is chosen at | |
769 | random. | |
770 | ||
771 | The valid range is 0 - 65535; the default value is 1. This option | |
772 | has effect only in balance-rr mode. | |
773 | ||
0307d589 VB |
774 | peer_notif_delay |
775 | ||
a362032e MCC |
776 | Specify the delay, in milliseconds, between each peer |
777 | notification (gratuitous ARP and unsolicited IPv6 Neighbor | |
778 | Advertisement) when they are issued after a failover event. | |
84df83e0 HL |
779 | This delay should be a multiple of the MII link monitor interval |
780 | (miimon). | |
781 | ||
782 | The valid range is 0 - 300000. The default value is 0, which means | |
783 | to match the value of the MII link monitor interval. | |
0307d589 | 784 | |
0a2ff7cc HL |
785 | prio |
786 | Slave priority. A higher number means higher priority. | |
787 | The primary slave has the highest priority. This option also | |
788 | follows the primary_reselect rules. | |
789 | ||
790 | This option could only be configured via netlink, and is only valid | |
791 | for active-backup(1), balance-tlb (5) and balance-alb (6) mode. | |
792 | The valid value range is a signed 32 bit integer. | |
793 | ||
794 | The default value is 0. | |
795 | ||
1da177e4 LT |
796 | primary |
797 | ||
798 | A string (eth0, eth2, etc) specifying which slave is the | |
799 | primary device. The specified device will always be the | |
800 | active slave while it is available. Only when the primary is | |
801 | off-line will alternate devices be used. This is useful when | |
802 | one slave is preferred over another, e.g., when one slave has | |
803 | higher throughput than another. | |
804 | ||
e1d206a7 | 805 | The primary option is only valid for active-backup(1), |
806 | balance-tlb (5) and balance-alb (6) mode. | |
1da177e4 | 807 | |
a549952a JP |
808 | primary_reselect |
809 | ||
810 | Specifies the reselection policy for the primary slave. This | |
811 | affects how the primary slave is chosen to become the active slave | |
812 | when failure of the active slave or recovery of the primary slave | |
813 | occurs. This option is designed to prevent flip-flopping between | |
814 | the primary slave and other slaves. Possible values are: | |
815 | ||
816 | always or 0 (default) | |
817 | ||
818 | The primary slave becomes the active slave whenever it | |
819 | comes back up. | |
820 | ||
821 | better or 1 | |
822 | ||
823 | The primary slave becomes the active slave when it comes | |
824 | back up, if the speed and duplex of the primary slave is | |
825 | better than the speed and duplex of the current active | |
826 | slave. | |
827 | ||
828 | failure or 2 | |
829 | ||
830 | The primary slave becomes the active slave only if the | |
831 | current active slave fails and the primary slave is up. | |
832 | ||
833 | The primary_reselect setting is ignored in two cases: | |
834 | ||
835 | If no slaves are active, the first slave to recover is | |
836 | made the active slave. | |
837 | ||
838 | When initially enslaved, the primary slave is always made | |
839 | the active slave. | |
840 | ||
841 | Changing the primary_reselect policy via sysfs will cause an | |
842 | immediate selection of the best active slave according to the new | |
843 | policy. This may or may not result in a change of the active | |
844 | slave, depending upon the circumstances. | |
845 | ||
846 | This option was added for bonding version 3.6.0. | |
847 | ||
e9f0fb88 MB |
848 | tlb_dynamic_lb |
849 | ||
850 | Specifies if dynamic shuffling of flows is enabled in tlb | |
fa872447 | 851 | or alb mode. The value has no effect on any other modes. |
e9f0fb88 MB |
852 | |
853 | The default behavior of tlb mode is to shuffle active flows across | |
854 | slaves based on the load in that interval. This gives nice lb | |
855 | characteristics but can cause packet reordering. If re-ordering is | |
856 | a concern use this variable to disable flow shuffling and rely on | |
857 | load balancing provided solely by the hash distribution. | |
858 | xmit-hash-policy can be used to select the appropriate hashing for | |
859 | the setup. | |
860 | ||
861 | The sysfs entry can be used to change the setting per bond device | |
862 | and the initial value is derived from the module parameter. The | |
863 | sysfs entry is allowed to be changed only if the bond device is | |
864 | down. | |
865 | ||
866 | The default value is "1" that enables flow shuffling while value "0" | |
867 | disables it. This option was added in bonding driver 3.7.1 | |
868 | ||
869 | ||
1da177e4 LT |
870 | updelay |
871 | ||
872 | Specifies the time, in milliseconds, to wait before enabling a | |
873 | slave after a link recovery has been detected. This option is | |
874 | only valid for the miimon link monitor. The updelay value | |
875 | should be a multiple of the miimon value; if not, it will be | |
876 | rounded down to the nearest multiple. The default value is 0. | |
877 | ||
878 | use_carrier | |
879 | ||
880 | Specifies whether or not miimon should use MII or ETHTOOL | |
881 | ioctls vs. netif_carrier_ok() to determine the link | |
882 | status. The MII or ETHTOOL ioctls are less efficient and | |
883 | utilize a deprecated calling sequence within the kernel. The | |
884 | netif_carrier_ok() relies on the device driver to maintain its | |
885 | state with netif_carrier_on/off; at this writing, most, but | |
886 | not all, device drivers support this facility. | |
887 | ||
888 | If bonding insists that the link is up when it should not be, | |
889 | it may be that your network device driver does not support | |
890 | netif_carrier_on/off. The default state for netif_carrier is | |
891 | "carrier on," so if a driver does not support netif_carrier, | |
892 | it will appear as if the link is always up. In this case, | |
893 | setting use_carrier to 0 will cause bonding to revert to the | |
894 | MII / ETHTOOL ioctl method to determine the link state. | |
895 | ||
896 | A value of 1 enables the use of netif_carrier_ok(), a value of | |
b3c898e2 DB |
897 | 0 will use the deprecated MII / ETHTOOL ioctls. The default |
898 | value is 1. | |
1da177e4 | 899 | |
00354cfb JV |
900 | xmit_hash_policy |
901 | ||
902 | Selects the transmit hash policy to use for slave selection in | |
f05b42ea | 903 | balance-xor, 802.3ad, and tlb modes. Possible values are: |
00354cfb JV |
904 | |
905 | layer2 | |
906 | ||
92abf750 JX |
907 | Uses XOR of hardware MAC addresses and packet type ID |
908 | field to generate the hash. The formula is | |
00354cfb | 909 | |
2cd1881b | 910 | hash = source MAC[5] XOR destination MAC[5] XOR packet type ID |
92abf750 | 911 | slave number = hash modulo slave count |
00354cfb JV |
912 | |
913 | This algorithm will place all traffic to a particular | |
914 | network peer on the same slave. | |
915 | ||
916 | This algorithm is 802.3ad compliant. | |
917 | ||
6f6652be JV |
918 | layer2+3 |
919 | ||
920 | This policy uses a combination of layer2 and layer3 | |
921 | protocol information to generate the hash. | |
922 | ||
923 | Uses XOR of hardware MAC addresses and IP addresses to | |
7a6afab1 | 924 | generate the hash. The formula is |
6f6652be | 925 | |
2cd1881b | 926 | hash = source MAC[5] XOR destination MAC[5] XOR packet type ID |
7a6afab1 NA |
927 | hash = hash XOR source IP XOR destination IP |
928 | hash = hash XOR (hash RSHIFT 16) | |
929 | hash = hash XOR (hash RSHIFT 8) | |
930 | And then hash is reduced modulo slave count. | |
6f6652be | 931 | |
7a6afab1 NA |
932 | If the protocol is IPv6 then the source and destination |
933 | addresses are first hashed using ipv6_addr_hash. | |
6b923cb7 | 934 | |
6f6652be JV |
935 | This algorithm will place all traffic to a particular |
936 | network peer on the same slave. For non-IP traffic, | |
937 | the formula is the same as for the layer2 transmit | |
938 | hash policy. | |
939 | ||
940 | This policy is intended to provide a more balanced | |
941 | distribution of traffic than layer2 alone, especially | |
942 | in environments where a layer3 gateway device is | |
943 | required to reach most destinations. | |
944 | ||
d9195881 | 945 | This algorithm is 802.3ad compliant. |
6f6652be | 946 | |
00354cfb JV |
947 | layer3+4 |
948 | ||
949 | This policy uses upper layer protocol information, | |
950 | when available, to generate the hash. This allows for | |
951 | traffic to a particular network peer to span multiple | |
952 | slaves, although a single connection will not span | |
953 | multiple slaves. | |
954 | ||
7a6afab1 | 955 | The formula for unfragmented TCP and UDP packets is |
00354cfb | 956 | |
7a6afab1 NA |
957 | hash = source port, destination port (as in the header) |
958 | hash = hash XOR source IP XOR destination IP | |
959 | hash = hash XOR (hash RSHIFT 16) | |
960 | hash = hash XOR (hash RSHIFT 8) | |
95cce3fa | 961 | hash = hash RSHIFT 1 |
7a6afab1 | 962 | And then hash is reduced modulo slave count. |
6b923cb7 | 963 | |
7a6afab1 NA |
964 | If the protocol is IPv6 then the source and destination |
965 | addresses are first hashed using ipv6_addr_hash. | |
6b923cb7 JE |
966 | |
967 | For fragmented TCP or UDP packets and all other IPv4 and | |
968 | IPv6 protocol traffic, the source and destination port | |
00354cfb JV |
969 | information is omitted. For non-IP traffic, the |
970 | formula is the same as for the layer2 transmit hash | |
971 | policy. | |
972 | ||
00354cfb JV |
973 | This algorithm is not fully 802.3ad compliant. A |
974 | single TCP or UDP conversation containing both | |
975 | fragmented and unfragmented packets will see packets | |
976 | striped across two interfaces. This may result in out | |
977 | of order delivery. Most traffic types will not meet | |
978 | this criteria, as TCP rarely fragments traffic, and | |
979 | most UDP traffic is not involved in extended | |
980 | conversations. Other implementations of 802.3ad may | |
981 | or may not tolerate this noncompliance. | |
982 | ||
7a6afab1 NA |
983 | encap2+3 |
984 | ||
985 | This policy uses the same formula as layer2+3 but it | |
986 | relies on skb_flow_dissect to obtain the header fields | |
987 | which might result in the use of inner headers if an | |
988 | encapsulation protocol is used. For example this will | |
989 | improve the performance for tunnel users because the | |
990 | packets will be distributed according to the encapsulated | |
991 | flows. | |
992 | ||
993 | encap3+4 | |
994 | ||
995 | This policy uses the same formula as layer3+4 but it | |
996 | relies on skb_flow_dissect to obtain the header fields | |
997 | which might result in the use of inner headers if an | |
998 | encapsulation protocol is used. For example this will | |
999 | improve the performance for tunnel users because the | |
1000 | packets will be distributed according to the encapsulated | |
1001 | flows. | |
1002 | ||
7b8fc010 JW |
1003 | vlan+srcmac |
1004 | ||
1005 | This policy uses a very rudimentary vlan ID and source mac | |
1006 | hash to load-balance traffic per-vlan, with failover | |
1007 | should one leg fail. The intended use case is for a bond | |
1008 | shared by multiple virtual machines, all configured to | |
1009 | use their own vlan, to give lacp-like functionality | |
1010 | without requiring lacp-capable switching hardware. | |
1011 | ||
1012 | The formula for the hash is simply | |
1013 | ||
1014 | hash = (vlan ID) XOR (source MAC vendor) XOR (source MAC dev) | |
1015 | ||
00354cfb | 1016 | The default value is layer2. This option was added in bonding |
6f6652be JV |
1017 | version 2.6.3. In earlier versions of bonding, this parameter |
1018 | does not exist, and the layer2 policy is the only policy. The | |
1019 | layer2+3 value was added for bonding version 3.2.2. | |
1da177e4 | 1020 | |
c2952c31 FL |
1021 | resend_igmp |
1022 | ||
1023 | Specifies the number of IGMP membership reports to be issued after | |
1024 | a failover event. One membership report is issued immediately after | |
1025 | the failover, subsequent packets are sent in each 200ms interval. | |
1026 | ||
94265cf5 FL |
1027 | The valid range is 0 - 255; the default value is 1. A value of 0 |
1028 | prevents the IGMP membership report from being issued in response | |
1029 | to the failover event. | |
1030 | ||
1031 | This option is useful for bonding modes balance-rr (0), active-backup | |
1032 | (1), balance-tlb (5) and balance-alb (6), in which a failover can | |
1033 | switch the IGMP traffic from one slave to another. Therefore a fresh | |
1034 | IGMP report must be issued to cause the switch to forward the incoming | |
1035 | IGMP traffic over the newly selected slave. | |
1036 | ||
1037 | This option was added for bonding version 3.7.0. | |
1da177e4 | 1038 | |
84a6a0ac | 1039 | lp_interval |
1040 | ||
1041 | Specifies the number of seconds between instances where the bonding | |
1042 | driver sends learning packets to each slaves peer switch. | |
1043 | ||
1044 | The valid range is 1 - 0x7fffffff; the default value is 1. This Option | |
1045 | has effect only in balance-tlb and balance-alb modes. | |
1046 | ||
1da177e4 LT |
1047 | 3. Configuring Bonding Devices |
1048 | ============================== | |
1049 | ||
a362032e | 1050 | You can configure bonding using either your distro's network |
b1098bbe | 1051 | initialization scripts, or manually using either iproute2 or the |
de221bd5 NP |
1052 | sysfs interface. Distros generally use one of three packages for the |
1053 | network initialization scripts: initscripts, sysconfig or interfaces. | |
1054 | Recent versions of these packages have support for bonding, while older | |
6224e01d | 1055 | versions do not. |
1da177e4 | 1056 | |
a362032e | 1057 | We will first describe the options for configuring bonding for |
de221bd5 NP |
1058 | distros using versions of initscripts, sysconfig and interfaces with full |
1059 | or partial support for bonding, then provide information on enabling | |
1da177e4 LT |
1060 | bonding without support from the network initialization scripts (i.e., |
1061 | older versions of initscripts or sysconfig). | |
1062 | ||
a362032e | 1063 | If you're unsure whether your distro uses sysconfig, |
de221bd5 | 1064 | initscripts or interfaces, or don't know if it's new enough, have no fear. |
1da177e4 LT |
1065 | Determining this is fairly straightforward. |
1066 | ||
a362032e | 1067 | First, look for a file called interfaces in /etc/network directory. |
de221bd5 NP |
1068 | If this file is present in your system, then your system use interfaces. See |
1069 | Configuration with Interfaces Support. | |
1070 | ||
a362032e | 1071 | Else, issue the command:: |
1da177e4 | 1072 | |
a362032e | 1073 | $ rpm -qf /sbin/ifup |
1da177e4 | 1074 | |
a362032e | 1075 | It will respond with a line of text starting with either |
1da177e4 LT |
1076 | "initscripts" or "sysconfig," followed by some numbers. This is the |
1077 | package that provides your network initialization scripts. | |
1078 | ||
a362032e MCC |
1079 | Next, to determine if your installation supports bonding, |
1080 | issue the command:: | |
1da177e4 | 1081 | |
a362032e | 1082 | $ grep ifenslave /sbin/ifup |
1da177e4 | 1083 | |
a362032e | 1084 | If this returns any matches, then your initscripts or |
1da177e4 LT |
1085 | sysconfig has support for bonding. |
1086 | ||
6224e01d | 1087 | 3.1 Configuration with Sysconfig Support |
1da177e4 LT |
1088 | ---------------------------------------- |
1089 | ||
a362032e | 1090 | This section applies to distros using a version of sysconfig |
1da177e4 LT |
1091 | with bonding support, for example, SuSE Linux Enterprise Server 9. |
1092 | ||
a362032e | 1093 | SuSE SLES 9's networking configuration system does support |
1da177e4 | 1094 | bonding, however, at this writing, the YaST system configuration |
6224e01d | 1095 | front end does not provide any means to work with bonding devices. |
1da177e4 LT |
1096 | Bonding devices can be managed by hand, however, as follows. |
1097 | ||
a362032e | 1098 | First, if they have not already been configured, configure the |
1da177e4 LT |
1099 | slave devices. On SLES 9, this is most easily done by running the |
1100 | yast2 sysconfig configuration utility. The goal is for to create an | |
1101 | ifcfg-id file for each slave device. The simplest way to accomplish | |
00354cfb JV |
1102 | this is to configure the devices for DHCP (this is only to get the |
1103 | file ifcfg-id file created; see below for some issues with DHCP). The | |
a362032e | 1104 | name of the configuration file for each device will be of the form:: |
1da177e4 | 1105 | |
a362032e | 1106 | ifcfg-id-xx:xx:xx:xx:xx:xx |
1da177e4 | 1107 | |
a362032e | 1108 | Where the "xx" portion will be replaced with the digits from |
1da177e4 LT |
1109 | the device's permanent MAC address. |
1110 | ||
a362032e | 1111 | Once the set of ifcfg-id-xx:xx:xx:xx:xx:xx files has been |
1da177e4 LT |
1112 | created, it is necessary to edit the configuration files for the slave |
1113 | devices (the MAC addresses correspond to those of the slave devices). | |
00354cfb | 1114 | Before editing, the file will contain multiple lines, and will look |
a362032e | 1115 | something like this:: |
1da177e4 | 1116 | |
a362032e MCC |
1117 | BOOTPROTO='dhcp' |
1118 | STARTMODE='on' | |
1119 | USERCTL='no' | |
1120 | UNIQUE='XNzu.WeZGOGF+4wE' | |
1121 | _nm_name='bus-pci-0001:61:01.0' | |
1da177e4 | 1122 | |
a362032e | 1123 | Change the BOOTPROTO and STARTMODE lines to the following:: |
1da177e4 | 1124 | |
a362032e MCC |
1125 | BOOTPROTO='none' |
1126 | STARTMODE='off' | |
1da177e4 | 1127 | |
a362032e | 1128 | Do not alter the UNIQUE or _nm_name lines. Remove any other |
1da177e4 LT |
1129 | lines (USERCTL, etc). |
1130 | ||
a362032e | 1131 | Once the ifcfg-id-xx:xx:xx:xx:xx:xx files have been modified, |
1da177e4 LT |
1132 | it's time to create the configuration file for the bonding device |
1133 | itself. This file is named ifcfg-bondX, where X is the number of the | |
1134 | bonding device to create, starting at 0. The first such file is | |
1135 | ifcfg-bond0, the second is ifcfg-bond1, and so on. The sysconfig | |
1136 | network configuration system will correctly start multiple instances | |
1137 | of bonding. | |
1138 | ||
a362032e MCC |
1139 | The contents of the ifcfg-bondX file is as follows:: |
1140 | ||
1141 | BOOTPROTO="static" | |
1142 | BROADCAST="10.0.2.255" | |
1143 | IPADDR="10.0.2.10" | |
1144 | NETMASK="255.255.0.0" | |
1145 | NETWORK="10.0.2.0" | |
1146 | REMOTE_IPADDR="" | |
1147 | STARTMODE="onboot" | |
1148 | BONDING_MASTER="yes" | |
1149 | BONDING_MODULE_OPTS="mode=active-backup miimon=100" | |
1150 | BONDING_SLAVE0="eth0" | |
1151 | BONDING_SLAVE1="bus-pci-0000:06:08.1" | |
1152 | ||
1153 | Replace the sample BROADCAST, IPADDR, NETMASK and NETWORK | |
1da177e4 LT |
1154 | values with the appropriate values for your network. |
1155 | ||
a362032e | 1156 | The STARTMODE specifies when the device is brought online. |
1da177e4 LT |
1157 | The possible values are: |
1158 | ||
a362032e MCC |
1159 | ======== ====================================================== |
1160 | onboot The device is started at boot time. If you're not | |
1da177e4 LT |
1161 | sure, this is probably what you want. |
1162 | ||
a362032e | 1163 | manual The device is started only when ifup is called |
1da177e4 LT |
1164 | manually. Bonding devices may be configured this |
1165 | way if you do not wish them to start automatically | |
1166 | at boot for some reason. | |
1167 | ||
a362032e | 1168 | hotplug The device is started by a hotplug event. This is not |
1da177e4 LT |
1169 | a valid choice for a bonding device. |
1170 | ||
a362032e MCC |
1171 | off or The device configuration is ignored. |
1172 | ignore | |
1173 | ======== ====================================================== | |
1da177e4 | 1174 | |
a362032e | 1175 | The line BONDING_MASTER='yes' indicates that the device is a |
1da177e4 LT |
1176 | bonding master device. The only useful value is "yes." |
1177 | ||
a362032e | 1178 | The contents of BONDING_MODULE_OPTS are supplied to the |
1da177e4 LT |
1179 | instance of the bonding module for this device. Specify the options |
1180 | for the bonding mode, link monitoring, and so on here. Do not include | |
1181 | the max_bonds bonding parameter; this will confuse the configuration | |
1182 | system if you have multiple bonding devices. | |
1183 | ||
a362032e | 1184 | Finally, supply one BONDING_SLAVEn="slave device" for each |
00354cfb JV |
1185 | slave. where "n" is an increasing value, one for each slave. The |
1186 | "slave device" is either an interface name, e.g., "eth0", or a device | |
1187 | specifier for the network device. The interface name is easier to | |
1188 | find, but the ethN names are subject to change at boot time if, e.g., | |
1189 | a device early in the sequence has failed. The device specifiers | |
1190 | (bus-pci-0000:06:08.1 in the example above) specify the physical | |
1191 | network device, and will not change unless the device's bus location | |
1192 | changes (for example, it is moved from one PCI slot to another). The | |
1193 | example above uses one of each type for demonstration purposes; most | |
1194 | configurations will choose one or the other for all slave devices. | |
1da177e4 | 1195 | |
a362032e | 1196 | When all configuration files have been modified or created, |
1da177e4 | 1197 | networking must be restarted for the configuration changes to take |
a362032e | 1198 | effect. This can be accomplished via the following:: |
1da177e4 | 1199 | |
a362032e | 1200 | # /etc/init.d/network restart |
1da177e4 | 1201 | |
a362032e | 1202 | Note that the network control script (/sbin/ifdown) will |
1da177e4 LT |
1203 | remove the bonding module as part of the network shutdown processing, |
1204 | so it is not necessary to remove the module by hand if, e.g., the | |
00354cfb | 1205 | module parameters have changed. |
1da177e4 | 1206 | |
a362032e | 1207 | Also, at this writing, YaST/YaST2 will not manage bonding |
1da177e4 LT |
1208 | devices (they do not show bonding interfaces on its list of network |
1209 | devices). It is necessary to edit the configuration file by hand to | |
1210 | change the bonding configuration. | |
1211 | ||
a362032e MCC |
1212 | Additional general options and details of the ifcfg file |
1213 | format can be found in an example ifcfg template file:: | |
1da177e4 | 1214 | |
a362032e | 1215 | /etc/sysconfig/network/ifcfg.template |
1da177e4 | 1216 | |
a362032e | 1217 | Note that the template does not document the various ``BONDING_*`` |
1da177e4 LT |
1218 | settings described above, but does describe many of the other options. |
1219 | ||
6224e01d | 1220 | 3.1.1 Using DHCP with Sysconfig |
00354cfb JV |
1221 | ------------------------------- |
1222 | ||
a362032e | 1223 | Under sysconfig, configuring a device with BOOTPROTO='dhcp' |
00354cfb JV |
1224 | will cause it to query DHCP for its IP address information. At this |
1225 | writing, this does not function for bonding devices; the scripts | |
1226 | attempt to obtain the device address from DHCP prior to adding any of | |
1227 | the slave devices. Without active slaves, the DHCP requests are not | |
1228 | sent to the network. | |
1229 | ||
6224e01d | 1230 | 3.1.2 Configuring Multiple Bonds with Sysconfig |
00354cfb JV |
1231 | ----------------------------------------------- |
1232 | ||
a362032e | 1233 | The sysconfig network initialization system is capable of |
00354cfb JV |
1234 | handling multiple bonding devices. All that is necessary is for each |
1235 | bonding instance to have an appropriately configured ifcfg-bondX file | |
1236 | (as described above). Do not specify the "max_bonds" parameter to any | |
1237 | instance of bonding, as this will confuse sysconfig. If you require | |
1238 | multiple bonding devices with identical parameters, create multiple | |
1239 | ifcfg-bondX files. | |
1240 | ||
a362032e | 1241 | Because the sysconfig scripts supply the bonding module |
00354cfb | 1242 | options in the ifcfg-bondX file, it is not necessary to add them to |
a362032e | 1243 | the system ``/etc/modules.d/*.conf`` configuration files. |
00354cfb | 1244 | |
6224e01d | 1245 | 3.2 Configuration with Initscripts Support |
1da177e4 LT |
1246 | ------------------------------------------ |
1247 | ||
a362032e | 1248 | This section applies to distros using a recent version of |
9a6c6867 JV |
1249 | initscripts with bonding support, for example, Red Hat Enterprise Linux |
1250 | version 3 or later, Fedora, etc. On these systems, the network | |
1251 | initialization scripts have knowledge of bonding, and can be configured to | |
1252 | control bonding devices. Note that older versions of the initscripts | |
1253 | package have lower levels of support for bonding; this will be noted where | |
1254 | applicable. | |
1da177e4 | 1255 | |
a362032e | 1256 | These distros will not automatically load the network adapter |
1da177e4 LT |
1257 | driver unless the ethX device is configured with an IP address. |
1258 | Because of this constraint, users must manually configure a | |
1259 | network-script file for all physical adapters that will be members of | |
1260 | a bondX link. Network script files are located in the directory: | |
1261 | ||
1262 | /etc/sysconfig/network-scripts | |
1263 | ||
a362032e | 1264 | The file name must be prefixed with "ifcfg-eth" and suffixed |
1da177e4 LT |
1265 | with the adapter's physical adapter number. For example, the script |
1266 | for eth0 would be named /etc/sysconfig/network-scripts/ifcfg-eth0. | |
a362032e | 1267 | Place the following text in the file:: |
1da177e4 | 1268 | |
a362032e MCC |
1269 | DEVICE=eth0 |
1270 | USERCTL=no | |
1271 | ONBOOT=yes | |
1272 | MASTER=bond0 | |
1273 | SLAVE=yes | |
1274 | BOOTPROTO=none | |
1da177e4 | 1275 | |
a362032e | 1276 | The DEVICE= line will be different for every ethX device and |
1da177e4 LT |
1277 | must correspond with the name of the file, i.e., ifcfg-eth1 must have |
1278 | a device line of DEVICE=eth1. The setting of the MASTER= line will | |
1279 | also depend on the final bonding interface name chosen for your bond. | |
1280 | As with other network devices, these typically start at 0, and go up | |
1281 | one for each device, i.e., the first bonding instance is bond0, the | |
1282 | second is bond1, and so on. | |
1283 | ||
a362032e | 1284 | Next, create a bond network script. The file name for this |
1da177e4 LT |
1285 | script will be /etc/sysconfig/network-scripts/ifcfg-bondX where X is |
1286 | the number of the bond. For bond0 the file is named "ifcfg-bond0", | |
1287 | for bond1 it is named "ifcfg-bond1", and so on. Within that file, | |
a362032e MCC |
1288 | place the following text:: |
1289 | ||
1290 | DEVICE=bond0 | |
1291 | IPADDR=192.168.1.1 | |
1292 | NETMASK=255.255.255.0 | |
1293 | NETWORK=192.168.1.0 | |
1294 | BROADCAST=192.168.1.255 | |
1295 | ONBOOT=yes | |
1296 | BOOTPROTO=none | |
1297 | USERCTL=no | |
1298 | ||
1299 | Be sure to change the networking specific lines (IPADDR, | |
1da177e4 LT |
1300 | NETMASK, NETWORK and BROADCAST) to match your network configuration. |
1301 | ||
a362032e | 1302 | For later versions of initscripts, such as that found with Fedora |
3f8b4b13 AG |
1303 | 7 (or later) and Red Hat Enterprise Linux version 5 (or later), it is possible, |
1304 | and, indeed, preferable, to specify the bonding options in the ifcfg-bond0 | |
a362032e | 1305 | file, e.g. a line of the format:: |
9a6c6867 | 1306 | |
a362032e | 1307 | BONDING_OPTS="mode=active-backup arp_interval=60 arp_ip_target=192.168.1.254" |
9a6c6867 | 1308 | |
a362032e | 1309 | will configure the bond with the specified options. The options |
9a6c6867 | 1310 | specified in BONDING_OPTS are identical to the bonding module parameters |
3f8b4b13 AG |
1311 | except for the arp_ip_target field when using versions of initscripts older |
1312 | than and 8.57 (Fedora 8) and 8.45.19 (Red Hat Enterprise Linux 5.2). When | |
1313 | using older versions each target should be included as a separate option and | |
1314 | should be preceded by a '+' to indicate it should be added to the list of | |
a362032e | 1315 | queried targets, e.g.,:: |
9a6c6867 | 1316 | |
a362032e | 1317 | arp_ip_target=+192.168.1.1 arp_ip_target=+192.168.1.2 |
9a6c6867 | 1318 | |
a362032e MCC |
1319 | is the proper syntax to specify multiple targets. When specifying |
1320 | options via BONDING_OPTS, it is not necessary to edit | |
1321 | ``/etc/modprobe.d/*.conf``. | |
9a6c6867 | 1322 | |
a362032e | 1323 | For even older versions of initscripts that do not support |
970e2486 LDM |
1324 | BONDING_OPTS, it is necessary to edit /etc/modprobe.d/*.conf, depending upon |
1325 | your distro) to load the bonding module with your desired options when the | |
1326 | bond0 interface is brought up. The following lines in /etc/modprobe.d/*.conf | |
1327 | will load the bonding module, and select its options: | |
1da177e4 | 1328 | |
a362032e MCC |
1329 | alias bond0 bonding |
1330 | options bond0 mode=balance-alb miimon=100 | |
1da177e4 | 1331 | |
a362032e | 1332 | Replace the sample parameters with the appropriate set of |
1da177e4 LT |
1333 | options for your configuration. |
1334 | ||
a362032e | 1335 | Finally run "/etc/rc.d/init.d/network restart" as root. This |
1da177e4 LT |
1336 | will restart the networking subsystem and your bond link should be now |
1337 | up and running. | |
1338 | ||
6224e01d | 1339 | 3.2.1 Using DHCP with Initscripts |
00354cfb JV |
1340 | --------------------------------- |
1341 | ||
a362032e | 1342 | Recent versions of initscripts (the versions supplied with Fedora |
9a6c6867 JV |
1343 | Core 3 and Red Hat Enterprise Linux 4, or later versions, are reported to |
1344 | work) have support for assigning IP information to bonding devices via | |
1345 | DHCP. | |
00354cfb | 1346 | |
a362032e | 1347 | To configure bonding for DHCP, configure it as described |
00354cfb JV |
1348 | above, except replace the line "BOOTPROTO=none" with "BOOTPROTO=dhcp" |
1349 | and add a line consisting of "TYPE=Bonding". Note that the TYPE value | |
1350 | is case sensitive. | |
1351 | ||
6224e01d | 1352 | 3.2.2 Configuring Multiple Bonds with Initscripts |
00354cfb JV |
1353 | ------------------------------------------------- |
1354 | ||
a362032e | 1355 | Initscripts packages that are included with Fedora 7 and Red Hat |
9a6c6867 JV |
1356 | Enterprise Linux 5 support multiple bonding interfaces by simply |
1357 | specifying the appropriate BONDING_OPTS= in ifcfg-bondX where X is the | |
1358 | number of the bond. This support requires sysfs support in the kernel, | |
1359 | and a bonding driver of version 3.0.0 or later. Other configurations may | |
1360 | not support this method for specifying multiple bonding interfaces; for | |
1361 | those instances, see the "Configuring Multiple Bonds Manually" section, | |
1362 | below. | |
1da177e4 | 1363 | |
b1098bbe | 1364 | 3.3 Configuring Bonding Manually with iproute2 |
6224e01d | 1365 | ----------------------------------------------- |
1da177e4 | 1366 | |
a362032e | 1367 | This section applies to distros whose network initialization |
1da177e4 LT |
1368 | scripts (the sysconfig or initscripts package) do not have specific |
1369 | knowledge of bonding. One such distro is SuSE Linux Enterprise Server | |
1370 | version 8. | |
1371 | ||
a362032e | 1372 | The general method for these systems is to place the bonding |
970e2486 | 1373 | module parameters into a config file in /etc/modprobe.d/ (as |
00354cfb | 1374 | appropriate for the installed distro), then add modprobe and/or |
b1098bbe | 1375 | `ip link` commands to the system's global init script. The name of |
00354cfb | 1376 | the global init script differs; for sysconfig, it is |
1da177e4 LT |
1377 | /etc/init.d/boot.local and for initscripts it is /etc/rc.d/rc.local. |
1378 | ||
a362032e | 1379 | For example, if you wanted to make a simple bond of two e100 |
1da177e4 LT |
1380 | devices (presumed to be eth0 and eth1), and have it persist across |
1381 | reboots, edit the appropriate file (/etc/init.d/boot.local or | |
a362032e | 1382 | /etc/rc.d/rc.local), and add the following:: |
1da177e4 | 1383 | |
a362032e MCC |
1384 | modprobe bonding mode=balance-alb miimon=100 |
1385 | modprobe e100 | |
1386 | ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up | |
1387 | ip link set eth0 master bond0 | |
1388 | ip link set eth1 master bond0 | |
1da177e4 | 1389 | |
a362032e | 1390 | Replace the example bonding module parameters and bond0 |
1da177e4 | 1391 | network configuration (IP address, netmask, etc) with the appropriate |
00354cfb | 1392 | values for your configuration. |
1da177e4 | 1393 | |
a362032e | 1394 | Unfortunately, this method will not provide support for the |
1da177e4 | 1395 | ifup and ifdown scripts on the bond devices. To reload the bonding |
a362032e | 1396 | configuration, it is necessary to run the initialization script, e.g.,:: |
1da177e4 | 1397 | |
a362032e | 1398 | # /etc/init.d/boot.local |
1da177e4 | 1399 | |
a362032e | 1400 | or:: |
1da177e4 | 1401 | |
a362032e | 1402 | # /etc/rc.d/rc.local |
1da177e4 | 1403 | |
a362032e | 1404 | It may be desirable in such a case to create a separate script |
1da177e4 LT |
1405 | which only initializes the bonding configuration, then call that |
1406 | separate script from within boot.local. This allows for bonding to be | |
1407 | enabled without re-running the entire global init script. | |
1408 | ||
a362032e | 1409 | To shut down the bonding devices, it is necessary to first |
1da177e4 LT |
1410 | mark the bonding device itself as being down, then remove the |
1411 | appropriate device driver modules. For our example above, you can do | |
a362032e | 1412 | the following:: |
1da177e4 | 1413 | |
a362032e MCC |
1414 | # ifconfig bond0 down |
1415 | # rmmod bonding | |
1416 | # rmmod e100 | |
1da177e4 | 1417 | |
a362032e | 1418 | Again, for convenience, it may be desirable to create a script |
1da177e4 LT |
1419 | with these commands. |
1420 | ||
1421 | ||
00354cfb JV |
1422 | 3.3.1 Configuring Multiple Bonds Manually |
1423 | ----------------------------------------- | |
1da177e4 | 1424 | |
a362032e | 1425 | This section contains information on configuring multiple |
00354cfb JV |
1426 | bonding devices with differing options for those systems whose network |
1427 | initialization scripts lack support for configuring multiple bonds. | |
1428 | ||
a362032e | 1429 | If you require multiple bonding devices, but all with the same |
00354cfb JV |
1430 | options, you may wish to use the "max_bonds" module parameter, |
1431 | documented above. | |
1da177e4 | 1432 | |
a362032e | 1433 | To create multiple bonding devices with differing options, it is |
f8b72d36 | 1434 | preferable to use bonding parameters exported by sysfs, documented in the |
9a6c6867 JV |
1435 | section below. |
1436 | ||
a362032e | 1437 | For versions of bonding without sysfs support, the only means to |
9a6c6867 JV |
1438 | provide multiple instances of bonding with differing options is to load |
1439 | the bonding driver multiple times. Note that current versions of the | |
1440 | sysconfig network initialization scripts handle this automatically; if | |
1441 | your distro uses these scripts, no special action is needed. See the | |
1442 | section Configuring Bonding Devices, above, if you're not sure about your | |
1443 | network initialization scripts. | |
1444 | ||
a362032e | 1445 | To load multiple instances of the module, it is necessary to |
9a6c6867 JV |
1446 | specify a different name for each instance (the module loading system |
1447 | requires that every loaded module, even multiple instances of the same | |
1448 | module, have a unique name). This is accomplished by supplying multiple | |
a362032e | 1449 | sets of bonding options in ``/etc/modprobe.d/*.conf``, for example:: |
9a6c6867 | 1450 | |
a362032e MCC |
1451 | alias bond0 bonding |
1452 | options bond0 -o bond0 mode=balance-rr miimon=100 | |
9a6c6867 | 1453 | |
a362032e MCC |
1454 | alias bond1 bonding |
1455 | options bond1 -o bond1 mode=balance-alb miimon=50 | |
9a6c6867 | 1456 | |
a362032e | 1457 | will load the bonding module two times. The first instance is |
9a6c6867 JV |
1458 | named "bond0" and creates the bond0 device in balance-rr mode with an |
1459 | miimon of 100. The second instance is named "bond1" and creates the | |
1460 | bond1 device in balance-alb mode with an miimon of 50. | |
1461 | ||
a362032e | 1462 | In some circumstances (typically with older distributions), |
9a6c6867 JV |
1463 | the above does not work, and the second bonding instance never sees |
1464 | its options. In that case, the second options line can be substituted | |
a362032e | 1465 | as follows:: |
9a6c6867 | 1466 | |
a362032e MCC |
1467 | install bond1 /sbin/modprobe --ignore-install bonding -o bond1 \ |
1468 | mode=balance-alb miimon=50 | |
00354cfb | 1469 | |
a362032e | 1470 | This may be repeated any number of times, specifying a new and |
9a6c6867 JV |
1471 | unique name in place of bond1 for each subsequent instance. |
1472 | ||
a362032e | 1473 | It has been observed that some Red Hat supplied kernels are unable |
9a6c6867 JV |
1474 | to rename modules at load time (the "-o bond1" part). Attempts to pass |
1475 | that option to modprobe will produce an "Operation not permitted" error. | |
1476 | This has been reported on some Fedora Core kernels, and has been seen on | |
1477 | RHEL 4 as well. On kernels exhibiting this problem, it will be impossible | |
1478 | to configure multiple bonds with differing parameters (as they are older | |
1479 | kernels, and also lack sysfs support). | |
1da177e4 | 1480 | |
6224e01d AK |
1481 | 3.4 Configuring Bonding Manually via Sysfs |
1482 | ------------------------------------------ | |
1483 | ||
a362032e | 1484 | Starting with version 3.0.0, Channel Bonding may be configured |
6224e01d AK |
1485 | via the sysfs interface. This interface allows dynamic configuration |
1486 | of all bonds in the system without unloading the module. It also | |
1487 | allows for adding and removing bonds at runtime. Ifenslave is no | |
1488 | longer required, though it is still supported. | |
1489 | ||
a362032e | 1490 | Use of the sysfs interface allows you to use multiple bonds |
6224e01d AK |
1491 | with different configurations without having to reload the module. |
1492 | It also allows you to use multiple, differently configured bonds when | |
1493 | bonding is compiled into the kernel. | |
1494 | ||
a362032e | 1495 | You must have the sysfs filesystem mounted to configure |
6224e01d AK |
1496 | bonding this way. The examples in this document assume that you |
1497 | are using the standard mount point for sysfs, e.g. /sys. If your | |
1498 | sysfs filesystem is mounted elsewhere, you will need to adjust the | |
1499 | example paths accordingly. | |
1500 | ||
1501 | Creating and Destroying Bonds | |
1502 | ----------------------------- | |
a362032e MCC |
1503 | To add a new bond foo:: |
1504 | ||
1505 | # echo +foo > /sys/class/net/bonding_masters | |
1506 | ||
1507 | To remove an existing bond bar:: | |
6224e01d | 1508 | |
a362032e | 1509 | # echo -bar > /sys/class/net/bonding_masters |
6224e01d | 1510 | |
a362032e | 1511 | To show all existing bonds:: |
6224e01d | 1512 | |
a362032e MCC |
1513 | # cat /sys/class/net/bonding_masters |
1514 | ||
1515 | .. note:: | |
1516 | ||
1517 | due to 4K size limitation of sysfs files, this list may be | |
1518 | truncated if you have more than a few hundred bonds. This is unlikely | |
1519 | to occur under normal operating conditions. | |
6224e01d AK |
1520 | |
1521 | Adding and Removing Slaves | |
1522 | -------------------------- | |
a362032e | 1523 | Interfaces may be enslaved to a bond using the file |
6224e01d AK |
1524 | /sys/class/net/<bond>/bonding/slaves. The semantics for this file |
1525 | are the same as for the bonding_masters file. | |
1526 | ||
a362032e MCC |
1527 | To enslave interface eth0 to bond bond0:: |
1528 | ||
1529 | # ifconfig bond0 up | |
1530 | # echo +eth0 > /sys/class/net/bond0/bonding/slaves | |
6224e01d | 1531 | |
a362032e | 1532 | To free slave eth0 from bond bond0:: |
6224e01d | 1533 | |
a362032e MCC |
1534 | # echo -eth0 > /sys/class/net/bond0/bonding/slaves |
1535 | ||
1536 | When an interface is enslaved to a bond, symlinks between the | |
6224e01d AK |
1537 | two are created in the sysfs filesystem. In this case, you would get |
1538 | /sys/class/net/bond0/slave_eth0 pointing to /sys/class/net/eth0, and | |
1539 | /sys/class/net/eth0/master pointing to /sys/class/net/bond0. | |
1540 | ||
a362032e | 1541 | This means that you can tell quickly whether or not an |
6224e01d AK |
1542 | interface is enslaved by looking for the master symlink. Thus: |
1543 | # echo -eth0 > /sys/class/net/eth0/master/bonding/slaves | |
1544 | will free eth0 from whatever bond it is enslaved to, regardless of | |
1545 | the name of the bond interface. | |
1546 | ||
1547 | Changing a Bond's Configuration | |
1548 | ------------------------------- | |
a362032e | 1549 | Each bond may be configured individually by manipulating the |
6224e01d AK |
1550 | files located in /sys/class/net/<bond name>/bonding |
1551 | ||
a362032e | 1552 | The names of these files correspond directly with the command- |
670e9f34 | 1553 | line parameters described elsewhere in this file, and, with the |
6224e01d AK |
1554 | exception of arp_ip_target, they accept the same values. To see the |
1555 | current setting, simply cat the appropriate file. | |
1556 | ||
a362032e | 1557 | A few examples will be given here; for specific usage |
6224e01d AK |
1558 | guidelines for each parameter, see the appropriate section in this |
1559 | document. | |
1560 | ||
a362032e MCC |
1561 | To configure bond0 for balance-alb mode:: |
1562 | ||
1563 | # ifconfig bond0 down | |
1564 | # echo 6 > /sys/class/net/bond0/bonding/mode | |
1565 | - or - | |
1566 | # echo balance-alb > /sys/class/net/bond0/bonding/mode | |
1567 | ||
1568 | .. note:: | |
1569 | ||
1570 | The bond interface must be down before the mode can be changed. | |
1571 | ||
1572 | To enable MII monitoring on bond0 with a 1 second interval:: | |
1573 | ||
1574 | # echo 1000 > /sys/class/net/bond0/bonding/miimon | |
1575 | ||
1576 | .. note:: | |
1577 | ||
1578 | If ARP monitoring is enabled, it will disabled when MII | |
1579 | monitoring is enabled, and vice-versa. | |
1580 | ||
1581 | To add ARP targets:: | |
1582 | ||
1583 | # echo +192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target | |
1584 | # echo +192.168.0.101 > /sys/class/net/bond0/bonding/arp_ip_target | |
1585 | ||
1586 | .. note:: | |
1587 | ||
1588 | up to 16 target addresses may be specified. | |
1589 | ||
1590 | To remove an ARP target:: | |
1591 | ||
1592 | # echo -192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target | |
1593 | ||
1594 | To configure the interval between learning packet transmits:: | |
1595 | ||
1596 | # echo 12 > /sys/class/net/bond0/bonding/lp_interval | |
1597 | ||
1598 | .. note:: | |
1599 | ||
1600 | the lp_interval is the number of seconds between instances where | |
1601 | the bonding driver sends learning packets to each slaves peer switch. The | |
1602 | default interval is 1 second. | |
7eacd038 | 1603 | |
6224e01d AK |
1604 | Example Configuration |
1605 | --------------------- | |
a362032e | 1606 | We begin with the same example that is shown in section 3.3, |
6224e01d AK |
1607 | executed with sysfs, and without using ifenslave. |
1608 | ||
a362032e | 1609 | To make a simple bond of two e100 devices (presumed to be eth0 |
6224e01d AK |
1610 | and eth1), and have it persist across reboots, edit the appropriate |
1611 | file (/etc/init.d/boot.local or /etc/rc.d/rc.local), and add the | |
a362032e | 1612 | following:: |
6224e01d | 1613 | |
a362032e MCC |
1614 | modprobe bonding |
1615 | modprobe e100 | |
1616 | echo balance-alb > /sys/class/net/bond0/bonding/mode | |
1617 | ifconfig bond0 192.168.1.1 netmask 255.255.255.0 up | |
1618 | echo 100 > /sys/class/net/bond0/bonding/miimon | |
1619 | echo +eth0 > /sys/class/net/bond0/bonding/slaves | |
1620 | echo +eth1 > /sys/class/net/bond0/bonding/slaves | |
6224e01d | 1621 | |
a362032e | 1622 | To add a second bond, with two e1000 interfaces in |
6224e01d | 1623 | active-backup mode, using ARP monitoring, add the following lines to |
a362032e | 1624 | your init script:: |
6224e01d | 1625 | |
a362032e MCC |
1626 | modprobe e1000 |
1627 | echo +bond1 > /sys/class/net/bonding_masters | |
1628 | echo active-backup > /sys/class/net/bond1/bonding/mode | |
1629 | ifconfig bond1 192.168.2.1 netmask 255.255.255.0 up | |
1630 | echo +192.168.2.100 /sys/class/net/bond1/bonding/arp_ip_target | |
1631 | echo 2000 > /sys/class/net/bond1/bonding/arp_interval | |
1632 | echo +eth2 > /sys/class/net/bond1/bonding/slaves | |
1633 | echo +eth3 > /sys/class/net/bond1/bonding/slaves | |
6224e01d | 1634 | |
de221bd5 NP |
1635 | 3.5 Configuration with Interfaces Support |
1636 | ----------------------------------------- | |
1637 | ||
a362032e | 1638 | This section applies to distros which use /etc/network/interfaces file |
de221bd5 NP |
1639 | to describe network interface configuration, most notably Debian and it's |
1640 | derivatives. | |
1641 | ||
a362032e | 1642 | The ifup and ifdown commands on Debian don't support bonding out of |
de221bd5 | 1643 | the box. The ifenslave-2.6 package should be installed to provide bonding |
a362032e MCC |
1644 | support. Once installed, this package will provide ``bond-*`` options |
1645 | to be used into /etc/network/interfaces. | |
de221bd5 | 1646 | |
a362032e | 1647 | Note that ifenslave-2.6 package will load the bonding module and use |
de221bd5 NP |
1648 | the ifenslave command when appropriate. |
1649 | ||
1650 | Example Configurations | |
1651 | ---------------------- | |
1652 | ||
1653 | In /etc/network/interfaces, the following stanza will configure bond0, in | |
a362032e | 1654 | active-backup mode, with eth0 and eth1 as slaves:: |
de221bd5 | 1655 | |
a362032e MCC |
1656 | auto bond0 |
1657 | iface bond0 inet dhcp | |
1658 | bond-slaves eth0 eth1 | |
1659 | bond-mode active-backup | |
1660 | bond-miimon 100 | |
1661 | bond-primary eth0 eth1 | |
de221bd5 NP |
1662 | |
1663 | If the above configuration doesn't work, you might have a system using | |
1664 | upstart for system startup. This is most notably true for recent | |
1665 | Ubuntu versions. The following stanza in /etc/network/interfaces will | |
a362032e MCC |
1666 | produce the same result on those systems:: |
1667 | ||
1668 | auto bond0 | |
1669 | iface bond0 inet dhcp | |
1670 | bond-slaves none | |
1671 | bond-mode active-backup | |
1672 | bond-miimon 100 | |
1673 | ||
1674 | auto eth0 | |
1675 | iface eth0 inet manual | |
1676 | bond-master bond0 | |
1677 | bond-primary eth0 eth1 | |
1678 | ||
1679 | auto eth1 | |
1680 | iface eth1 inet manual | |
1681 | bond-master bond0 | |
1682 | bond-primary eth0 eth1 | |
1683 | ||
1684 | For a full list of ``bond-*`` supported options in /etc/network/interfaces and | |
1685 | some more advanced examples tailored to you particular distros, see the files in | |
de221bd5 NP |
1686 | /usr/share/doc/ifenslave-2.6. |
1687 | ||
1688 | 3.6 Overriding Configuration for Special Cases | |
bb1d9123 | 1689 | ---------------------------------------------- |
de221bd5 | 1690 | |
bb1d9123 AG |
1691 | When using the bonding driver, the physical port which transmits a frame is |
1692 | typically selected by the bonding driver, and is not relevant to the user or | |
1693 | system administrator. The output port is simply selected using the policies of | |
1694 | the selected bonding mode. On occasion however, it is helpful to direct certain | |
1695 | classes of traffic to certain physical interfaces on output to implement | |
1696 | slightly more complex policies. For example, to reach a web server over a | |
1697 | bonded interface in which eth0 connects to a private network, while eth1 | |
1698 | connects via a public network, it may be desirous to bias the bond to send said | |
1699 | traffic over eth0 first, using eth1 only as a fall back, while all other traffic | |
1700 | can safely be sent over either interface. Such configurations may be achieved | |
1701 | using the traffic control utilities inherent in linux. | |
1702 | ||
1703 | By default the bonding driver is multiqueue aware and 16 queues are created | |
e98aa682 | 1704 | when the driver initializes (see Documentation/networking/multiqueue.rst |
bb1d9123 AG |
1705 | for details). If more or less queues are desired the module parameter |
1706 | tx_queues can be used to change this value. There is no sysfs parameter | |
1707 | available as the allocation is done at module init time. | |
1708 | ||
1709 | The output of the file /proc/net/bonding/bondX has changed so the output Queue | |
a362032e | 1710 | ID is now printed for each slave:: |
bb1d9123 | 1711 | |
a362032e MCC |
1712 | Bonding Mode: fault-tolerance (active-backup) |
1713 | Primary Slave: None | |
1714 | Currently Active Slave: eth0 | |
1715 | MII Status: up | |
1716 | MII Polling Interval (ms): 0 | |
1717 | Up Delay (ms): 0 | |
1718 | Down Delay (ms): 0 | |
bb1d9123 | 1719 | |
a362032e MCC |
1720 | Slave Interface: eth0 |
1721 | MII Status: up | |
1722 | Link Failure Count: 0 | |
1723 | Permanent HW addr: 00:1a:a0:12:8f:cb | |
1724 | Slave queue ID: 0 | |
bb1d9123 | 1725 | |
a362032e MCC |
1726 | Slave Interface: eth1 |
1727 | MII Status: up | |
1728 | Link Failure Count: 0 | |
1729 | Permanent HW addr: 00:1a:a0:12:8f:cc | |
1730 | Slave queue ID: 2 | |
bb1d9123 | 1731 | |
a362032e | 1732 | The queue_id for a slave can be set using the command:: |
bb1d9123 | 1733 | |
a362032e | 1734 | # echo "eth1:2" > /sys/class/net/bond0/bonding/queue_id |
bb1d9123 AG |
1735 | |
1736 | Any interface that needs a queue_id set should set it with multiple calls | |
1737 | like the one above until proper priorities are set for all interfaces. On | |
1738 | distributions that allow configuration via initscripts, multiple 'queue_id' | |
1739 | arguments can be added to BONDING_OPTS to set all needed slave queues. | |
1740 | ||
1741 | These queue id's can be used in conjunction with the tc utility to configure | |
1742 | a multiqueue qdisc and filters to bias certain traffic to transmit on certain | |
1743 | slave devices. For instance, say we wanted, in the above configuration to | |
1744 | force all traffic bound to 192.168.1.100 to use eth1 in the bond as its output | |
a362032e | 1745 | device. The following commands would accomplish this:: |
bb1d9123 | 1746 | |
a362032e | 1747 | # tc qdisc add dev bond0 handle 1 root multiq |
bb1d9123 | 1748 | |
a362032e MCC |
1749 | # tc filter add dev bond0 protocol ip parent 1: prio 1 u32 match ip \ |
1750 | dst 192.168.1.100 action skbedit queue_mapping 2 | |
bb1d9123 AG |
1751 | |
1752 | These commands tell the kernel to attach a multiqueue queue discipline to the | |
1753 | bond0 interface and filter traffic enqueued to it, such that packets with a dst | |
1754 | ip of 192.168.1.100 have their output queue mapping value overwritten to 2. | |
1755 | This value is then passed into the driver, causing the normal output path | |
1756 | selection policy to be overridden, selecting instead qid 2, which maps to eth1. | |
1757 | ||
1758 | Note that qid values begin at 1. Qid 0 is reserved to initiate to the driver | |
1759 | that normal output policy selection should take place. One benefit to simply | |
1760 | leaving the qid for a slave to 0 is the multiqueue awareness in the bonding | |
1761 | driver that is now present. This awareness allows tc filters to be placed on | |
1762 | slave devices as well as bond devices and the bonding driver will simply act as | |
a362032e | 1763 | a pass-through for selecting output queues on the slave device rather than |
bb1d9123 AG |
1764 | output port selection. |
1765 | ||
1766 | This feature first appeared in bonding driver version 3.7.0 and support for | |
1767 | output slave selection was limited to round-robin and active-backup modes. | |
1768 | ||
d22a5fc0 MB |
1769 | 3.7 Configuring LACP for 802.3ad mode in a more secure way |
1770 | ---------------------------------------------------------- | |
1771 | ||
1772 | When using 802.3ad bonding mode, the Actor (host) and Partner (switch) | |
1773 | exchange LACPDUs. These LACPDUs cannot be sniffed, because they are | |
1774 | destined to link local mac addresses (which switches/bridges are not | |
1775 | supposed to forward). However, most of the values are easily predictable | |
1776 | or are simply the machine's MAC address (which is trivially known to all | |
1777 | other hosts in the same L2). This implies that other machines in the L2 | |
1778 | domain can spoof LACPDU packets from other hosts to the switch and potentially | |
1779 | cause mayhem by joining (from the point of view of the switch) another | |
1780 | machine's aggregate, thus receiving a portion of that hosts incoming | |
1781 | traffic and / or spoofing traffic from that machine themselves (potentially | |
1782 | even successfully terminating some portion of flows). Though this is not | |
1783 | a likely scenario, one could avoid this possibility by simply configuring | |
1784 | few bonding parameters: | |
1785 | ||
1786 | (a) ad_actor_system : You can set a random mac-address that can be used for | |
1787 | these LACPDU exchanges. The value can not be either NULL or Multicast. | |
1788 | Also it's preferable to set the local-admin bit. Following shell code | |
a362032e | 1789 | generates a random mac-address as described above:: |
d22a5fc0 | 1790 | |
a362032e MCC |
1791 | # sys_mac_addr=$(printf '%02x:%02x:%02x:%02x:%02x:%02x' \ |
1792 | $(( (RANDOM & 0xFE) | 0x02 )) \ | |
1793 | $(( RANDOM & 0xFF )) \ | |
1794 | $(( RANDOM & 0xFF )) \ | |
1795 | $(( RANDOM & 0xFF )) \ | |
1796 | $(( RANDOM & 0xFF )) \ | |
1797 | $(( RANDOM & 0xFF ))) | |
1798 | # echo $sys_mac_addr > /sys/class/net/bond0/bonding/ad_actor_system | |
d22a5fc0 MB |
1799 | |
1800 | (b) ad_actor_sys_prio : Randomize the system priority. The default value | |
1801 | is 65535, but system can take the value from 1 - 65535. Following shell | |
a362032e | 1802 | code generates random priority and sets it:: |
d22a5fc0 | 1803 | |
a362032e MCC |
1804 | # sys_prio=$(( 1 + RANDOM + RANDOM )) |
1805 | # echo $sys_prio > /sys/class/net/bond0/bonding/ad_actor_sys_prio | |
d22a5fc0 MB |
1806 | |
1807 | (c) ad_user_port_key : Use the user portion of the port-key. The default | |
1808 | keeps this empty. These are the upper 10 bits of the port-key and value | |
1809 | ranges from 0 - 1023. Following shell code generates these 10 bits and | |
a362032e | 1810 | sets it:: |
d22a5fc0 | 1811 | |
a362032e MCC |
1812 | # usr_port_key=$(( RANDOM & 0x3FF )) |
1813 | # echo $usr_port_key > /sys/class/net/bond0/bonding/ad_user_port_key | |
d22a5fc0 MB |
1814 | |
1815 | ||
bb1d9123 | 1816 | 4 Querying Bonding Configuration |
1da177e4 LT |
1817 | ================================= |
1818 | ||
6224e01d | 1819 | 4.1 Bonding Configuration |
1da177e4 LT |
1820 | ------------------------- |
1821 | ||
a362032e | 1822 | Each bonding device has a read-only file residing in the |
1da177e4 LT |
1823 | /proc/net/bonding directory. The file contents include information |
1824 | about the bonding configuration, options and state of each slave. | |
1825 | ||
a362032e | 1826 | For example, the contents of /proc/net/bonding/bond0 after the |
1da177e4 | 1827 | driver is loaded with parameters of mode=0 and miimon=1000 is |
a362032e | 1828 | generally as follows:: |
1da177e4 LT |
1829 | |
1830 | Ethernet Channel Bonding Driver: 2.6.1 (October 29, 2004) | |
a362032e MCC |
1831 | Bonding Mode: load balancing (round-robin) |
1832 | Currently Active Slave: eth0 | |
1833 | MII Status: up | |
1834 | MII Polling Interval (ms): 1000 | |
1835 | Up Delay (ms): 0 | |
1836 | Down Delay (ms): 0 | |
1837 | ||
1838 | Slave Interface: eth1 | |
1839 | MII Status: up | |
1840 | Link Failure Count: 1 | |
1841 | ||
1842 | Slave Interface: eth0 | |
1843 | MII Status: up | |
1844 | Link Failure Count: 1 | |
1845 | ||
1846 | The precise format and contents will change depending upon the | |
1da177e4 LT |
1847 | bonding configuration, state, and version of the bonding driver. |
1848 | ||
6224e01d | 1849 | 4.2 Network configuration |
1da177e4 LT |
1850 | ------------------------- |
1851 | ||
a362032e | 1852 | The network configuration can be inspected using the ifconfig |
1da177e4 LT |
1853 | command. Bonding devices will have the MASTER flag set; Bonding slave |
1854 | devices will have the SLAVE flag set. The ifconfig output does not | |
1855 | contain information on which slaves are associated with which masters. | |
1856 | ||
a362032e | 1857 | In the example below, the bond0 interface is the master |
1da177e4 LT |
1858 | (MASTER) while eth0 and eth1 are slaves (SLAVE). Notice all slaves of |
1859 | bond0 have the same MAC address (HWaddr) as bond0 for all modes except | |
a362032e MCC |
1860 | TLB and ALB that require a unique MAC address for each slave:: |
1861 | ||
1862 | # /sbin/ifconfig | |
1863 | bond0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1864 | inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0 | |
1865 | UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1 | |
1866 | RX packets:7224794 errors:0 dropped:0 overruns:0 frame:0 | |
1867 | TX packets:3286647 errors:1 dropped:0 overruns:1 carrier:0 | |
1868 | collisions:0 txqueuelen:0 | |
1869 | ||
1870 | eth0 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1871 | UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 | |
1872 | RX packets:3573025 errors:0 dropped:0 overruns:0 frame:0 | |
1873 | TX packets:1643167 errors:1 dropped:0 overruns:1 carrier:0 | |
1874 | collisions:0 txqueuelen:100 | |
1875 | Interrupt:10 Base address:0x1080 | |
1876 | ||
1877 | eth1 Link encap:Ethernet HWaddr 00:C0:F0:1F:37:B4 | |
1878 | UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 | |
1879 | RX packets:3651769 errors:0 dropped:0 overruns:0 frame:0 | |
1880 | TX packets:1643480 errors:0 dropped:0 overruns:0 carrier:0 | |
1881 | collisions:0 txqueuelen:100 | |
1882 | Interrupt:9 Base address:0x1400 | |
1da177e4 | 1883 | |
6224e01d | 1884 | 5. Switch Configuration |
1da177e4 LT |
1885 | ======================= |
1886 | ||
a362032e | 1887 | For this section, "switch" refers to whatever system the |
1da177e4 LT |
1888 | bonded devices are directly connected to (i.e., where the other end of |
1889 | the cable plugs into). This may be an actual dedicated switch device, | |
1890 | or it may be another regular system (e.g., another computer running | |
1891 | Linux), | |
1892 | ||
a362032e | 1893 | The active-backup, balance-tlb and balance-alb modes do not |
1da177e4 LT |
1894 | require any specific configuration of the switch. |
1895 | ||
a362032e | 1896 | The 802.3ad mode requires that the switch have the appropriate |
1da177e4 LT |
1897 | ports configured as an 802.3ad aggregation. The precise method used |
1898 | to configure this varies from switch to switch, but, for example, a | |
1899 | Cisco 3550 series switch requires that the appropriate ports first be | |
1900 | grouped together in a single etherchannel instance, then that | |
1901 | etherchannel is set to mode "lacp" to enable 802.3ad (instead of | |
1902 | standard EtherChannel). | |
1903 | ||
a362032e | 1904 | The balance-rr, balance-xor and broadcast modes generally |
1da177e4 LT |
1905 | require that the switch have the appropriate ports grouped together. |
1906 | The nomenclature for such a group differs between switches, it may be | |
1907 | called an "etherchannel" (as in the Cisco example, above), a "trunk | |
1908 | group" or some other similar variation. For these modes, each switch | |
1909 | will also have its own configuration options for the switch's transmit | |
1910 | policy to the bond. Typical choices include XOR of either the MAC or | |
1911 | IP addresses. The transmit policy of the two peers does not need to | |
1912 | match. For these three modes, the bonding mode really selects a | |
1913 | transmit policy for an EtherChannel group; all three will interoperate | |
1914 | with another EtherChannel group. | |
1915 | ||
1916 | ||
6224e01d | 1917 | 6. 802.1q VLAN Support |
1da177e4 LT |
1918 | ====================== |
1919 | ||
a362032e | 1920 | It is possible to configure VLAN devices over a bond interface |
1da177e4 LT |
1921 | using the 8021q driver. However, only packets coming from the 8021q |
1922 | driver and passing through bonding will be tagged by default. Self | |
1923 | generated packets, for example, bonding's learning packets or ARP | |
1924 | packets generated by either ALB mode or the ARP monitor mechanism, are | |
1925 | tagged internally by bonding itself. As a result, bonding must | |
1926 | "learn" the VLAN IDs configured above it, and use those IDs to tag | |
1927 | self generated packets. | |
1928 | ||
a362032e | 1929 | For reasons of simplicity, and to support the use of adapters |
00354cfb JV |
1930 | that can do VLAN hardware acceleration offloading, the bonding |
1931 | interface declares itself as fully hardware offloading capable, it gets | |
1da177e4 LT |
1932 | the add_vid/kill_vid notifications to gather the necessary |
1933 | information, and it propagates those actions to the slaves. In case | |
1934 | of mixed adapter types, hardware accelerated tagged packets that | |
1935 | should go through an adapter that is not offloading capable are | |
1936 | "un-accelerated" by the bonding driver so the VLAN tag sits in the | |
1937 | regular location. | |
1938 | ||
a362032e | 1939 | VLAN interfaces *must* be added on top of a bonding interface |
1da177e4 LT |
1940 | only after enslaving at least one slave. The bonding interface has a |
1941 | hardware address of 00:00:00:00:00:00 until the first slave is added. | |
1942 | If the VLAN interface is created prior to the first enslavement, it | |
1943 | would pick up the all-zeroes hardware address. Once the first slave | |
1944 | is attached to the bond, the bond device itself will pick up the | |
1945 | slave's hardware address, which is then available for the VLAN device. | |
1946 | ||
a362032e | 1947 | Also, be aware that a similar problem can occur if all slaves |
1da177e4 LT |
1948 | are released from a bond that still has one or more VLAN interfaces on |
1949 | top of it. When a new slave is added, the bonding interface will | |
1950 | obtain its hardware address from the first slave, which might not | |
1951 | match the hardware address of the VLAN interfaces (which was | |
1952 | ultimately copied from an earlier slave). | |
1953 | ||
a362032e | 1954 | There are two methods to insure that the VLAN device operates |
1da177e4 LT |
1955 | with the correct hardware address if all slaves are removed from a |
1956 | bond interface: | |
1957 | ||
a362032e | 1958 | 1. Remove all VLAN interfaces then recreate them |
1da177e4 | 1959 | |
a362032e | 1960 | 2. Set the bonding interface's hardware address so that it |
1da177e4 LT |
1961 | matches the hardware address of the VLAN interfaces. |
1962 | ||
a362032e | 1963 | Note that changing a VLAN interface's HW address would set the |
00354cfb | 1964 | underlying device -- i.e. the bonding interface -- to promiscuous |
1da177e4 LT |
1965 | mode, which might not be what you want. |
1966 | ||
1967 | ||
6224e01d | 1968 | 7. Link Monitoring |
1da177e4 LT |
1969 | ================== |
1970 | ||
a362032e | 1971 | The bonding driver at present supports two schemes for |
1da177e4 LT |
1972 | monitoring a slave device's link state: the ARP monitor and the MII |
1973 | monitor. | |
1974 | ||
a362032e | 1975 | At the present time, due to implementation restrictions in the |
1da177e4 LT |
1976 | bonding driver itself, it is not possible to enable both ARP and MII |
1977 | monitoring simultaneously. | |
1978 | ||
6224e01d | 1979 | 7.1 ARP Monitor Operation |
1da177e4 LT |
1980 | ------------------------- |
1981 | ||
a362032e | 1982 | The ARP monitor operates as its name suggests: it sends ARP |
1da177e4 LT |
1983 | queries to one or more designated peer systems on the network, and |
1984 | uses the response as an indication that the link is operating. This | |
1985 | gives some assurance that traffic is actually flowing to and from one | |
1986 | or more peers on the local network. | |
1987 | ||
6224e01d | 1988 | 7.2 Configuring Multiple ARP Targets |
1da177e4 LT |
1989 | ------------------------------------ |
1990 | ||
a362032e | 1991 | While ARP monitoring can be done with just one target, it can |
1da177e4 LT |
1992 | be useful in a High Availability setup to have several targets to |
1993 | monitor. In the case of just one target, the target itself may go | |
1994 | down or have a problem making it unresponsive to ARP requests. Having | |
1995 | an additional target (or several) increases the reliability of the ARP | |
1996 | monitoring. | |
1997 | ||
a362032e | 1998 | Multiple ARP targets must be separated by commas as follows:: |
1da177e4 | 1999 | |
a362032e MCC |
2000 | # example options for ARP monitoring with three targets |
2001 | alias bond0 bonding | |
2002 | options bond0 arp_interval=60 arp_ip_target=192.168.0.1,192.168.0.3,192.168.0.9 | |
1da177e4 | 2003 | |
a362032e | 2004 | For just a single target the options would resemble:: |
1da177e4 | 2005 | |
a362032e MCC |
2006 | # example options for ARP monitoring with one target |
2007 | alias bond0 bonding | |
2008 | options bond0 arp_interval=60 arp_ip_target=192.168.0.100 | |
1da177e4 LT |
2009 | |
2010 | ||
6224e01d | 2011 | 7.3 MII Monitor Operation |
1da177e4 LT |
2012 | ------------------------- |
2013 | ||
a362032e | 2014 | The MII monitor monitors only the carrier state of the local |
1da177e4 LT |
2015 | network interface. It accomplishes this in one of three ways: by |
2016 | depending upon the device driver to maintain its carrier state, by | |
2017 | querying the device's MII registers, or by making an ethtool query to | |
2018 | the device. | |
2019 | ||
a362032e | 2020 | If the use_carrier module parameter is 1 (the default value), |
1da177e4 LT |
2021 | then the MII monitor will rely on the driver for carrier state |
2022 | information (via the netif_carrier subsystem). As explained in the | |
2023 | use_carrier parameter information, above, if the MII monitor fails to | |
2024 | detect carrier loss on the device (e.g., when the cable is physically | |
2025 | disconnected), it may be that the driver does not support | |
2026 | netif_carrier. | |
2027 | ||
a362032e | 2028 | If use_carrier is 0, then the MII monitor will first query the |
1da177e4 LT |
2029 | device's (via ioctl) MII registers and check the link state. If that |
2030 | request fails (not just that it returns carrier down), then the MII | |
2353db75 | 2031 | monitor will make an ethtool ETHTOOL_GLINK request to attempt to obtain |
1da177e4 LT |
2032 | the same information. If both methods fail (i.e., the driver either |
2033 | does not support or had some error in processing both the MII register | |
2034 | and ethtool requests), then the MII monitor will assume the link is | |
2035 | up. | |
2036 | ||
6224e01d | 2037 | 8. Potential Sources of Trouble |
1da177e4 LT |
2038 | =============================== |
2039 | ||
6224e01d | 2040 | 8.1 Adventures in Routing |
1da177e4 LT |
2041 | ------------------------- |
2042 | ||
a362032e | 2043 | When bonding is configured, it is important that the slave |
6224e01d | 2044 | devices not have routes that supersede routes of the master (or, |
1da177e4 LT |
2045 | generally, not have routes at all). For example, suppose the bonding |
2046 | device bond0 has two slaves, eth0 and eth1, and the routing table is | |
a362032e | 2047 | as follows:: |
1da177e4 | 2048 | |
a362032e MCC |
2049 | Kernel IP routing table |
2050 | Destination Gateway Genmask Flags MSS Window irtt Iface | |
2051 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth0 | |
2052 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth1 | |
2053 | 10.0.0.0 0.0.0.0 255.255.0.0 U 40 0 0 bond0 | |
2054 | 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo | |
1da177e4 | 2055 | |
a362032e | 2056 | This routing configuration will likely still update the |
1da177e4 LT |
2057 | receive/transmit times in the driver (needed by the ARP monitor), but |
2058 | may bypass the bonding driver (because outgoing traffic to, in this | |
2059 | case, another host on network 10 would use eth0 or eth1 before bond0). | |
2060 | ||
a362032e | 2061 | The ARP monitor (and ARP itself) may become confused by this |
1da177e4 LT |
2062 | configuration, because ARP requests (generated by the ARP monitor) |
2063 | will be sent on one interface (bond0), but the corresponding reply | |
2064 | will arrive on a different interface (eth0). This reply looks to ARP | |
2065 | as an unsolicited ARP reply (because ARP matches replies on an | |
2066 | interface basis), and is discarded. The MII monitor is not affected | |
2067 | by the state of the routing table. | |
2068 | ||
a362032e | 2069 | The solution here is simply to insure that slaves do not have |
1da177e4 | 2070 | routes of their own, and if for some reason they must, those routes do |
6224e01d | 2071 | not supersede routes of their master. This should generally be the |
1da177e4 LT |
2072 | case, but unusual configurations or errant manual or automatic static |
2073 | route additions may cause trouble. | |
2074 | ||
6224e01d | 2075 | 8.2 Ethernet Device Renaming |
1da177e4 LT |
2076 | ---------------------------- |
2077 | ||
a362032e | 2078 | On systems with network configuration scripts that do not |
1da177e4 LT |
2079 | associate physical devices directly with network interface names (so |
2080 | that the same physical device always has the same "ethX" name), it may | |
970e2486 LDM |
2081 | be necessary to add some special logic to config files in |
2082 | /etc/modprobe.d/. | |
1da177e4 | 2083 | |
a362032e | 2084 | For example, given a modules.conf containing the following:: |
1da177e4 | 2085 | |
a362032e MCC |
2086 | alias bond0 bonding |
2087 | options bond0 mode=some-mode miimon=50 | |
2088 | alias eth0 tg3 | |
2089 | alias eth1 tg3 | |
2090 | alias eth2 e1000 | |
2091 | alias eth3 e1000 | |
1da177e4 | 2092 | |
a362032e | 2093 | If neither eth0 and eth1 are slaves to bond0, then when the |
1da177e4 LT |
2094 | bond0 interface comes up, the devices may end up reordered. This |
2095 | happens because bonding is loaded first, then its slave device's | |
2096 | drivers are loaded next. Since no other drivers have been loaded, | |
2097 | when the e1000 driver loads, it will receive eth0 and eth1 for its | |
2098 | devices, but the bonding configuration tries to enslave eth2 and eth3 | |
2099 | (which may later be assigned to the tg3 devices). | |
2100 | ||
a362032e | 2101 | Adding the following:: |
1da177e4 | 2102 | |
a362032e | 2103 | add above bonding e1000 tg3 |
1da177e4 | 2104 | |
a362032e | 2105 | causes modprobe to load e1000 then tg3, in that order, when |
1da177e4 LT |
2106 | bonding is loaded. This command is fully documented in the |
2107 | modules.conf manual page. | |
2108 | ||
a362032e | 2109 | On systems utilizing modprobe an equivalent problem can occur. |
970e2486 | 2110 | In this case, the following can be added to config files in |
a362032e | 2111 | /etc/modprobe.d/ as:: |
1da177e4 | 2112 | |
a362032e | 2113 | softdep bonding pre: tg3 e1000 |
1da177e4 | 2114 | |
a362032e | 2115 | This will load tg3 and e1000 modules before loading the bonding one. |
970e2486 LDM |
2116 | Full documentation on this can be found in the modprobe.d and modprobe |
2117 | manual pages. | |
1da177e4 | 2118 | |
6224e01d | 2119 | 8.3. Painfully Slow Or No Failed Link Detection By Miimon |
1da177e4 LT |
2120 | --------------------------------------------------------- |
2121 | ||
a362032e | 2122 | By default, bonding enables the use_carrier option, which |
1da177e4 LT |
2123 | instructs bonding to trust the driver to maintain carrier state. |
2124 | ||
a362032e | 2125 | As discussed in the options section, above, some drivers do |
1da177e4 LT |
2126 | not support the netif_carrier_on/_off link state tracking system. |
2127 | With use_carrier enabled, bonding will always see these links as up, | |
2128 | regardless of their actual state. | |
2129 | ||
a362032e | 2130 | Additionally, other drivers do support netif_carrier, but do |
1da177e4 LT |
2131 | not maintain it in real time, e.g., only polling the link state at |
2132 | some fixed interval. In this case, miimon will detect failures, but | |
2133 | only after some long period of time has expired. If it appears that | |
2134 | miimon is very slow in detecting link failures, try specifying | |
2135 | use_carrier=0 to see if that improves the failure detection time. If | |
2136 | it does, then it may be that the driver checks the carrier state at a | |
2137 | fixed interval, but does not cache the MII register values (so the | |
2138 | use_carrier=0 method of querying the registers directly works). If | |
2139 | use_carrier=0 does not improve the failover, then the driver may cache | |
2140 | the registers, or the problem may be elsewhere. | |
2141 | ||
a362032e | 2142 | Also, remember that miimon only checks for the device's |
1da177e4 LT |
2143 | carrier state. It has no way to determine the state of devices on or |
2144 | beyond other ports of a switch, or if a switch is refusing to pass | |
2145 | traffic while still maintaining carrier on. | |
2146 | ||
6224e01d | 2147 | 9. SNMP agents |
1da177e4 LT |
2148 | =============== |
2149 | ||
a362032e | 2150 | If running SNMP agents, the bonding driver should be loaded |
1da177e4 | 2151 | before any network drivers participating in a bond. This requirement |
d533f671 | 2152 | is due to the interface index (ipAdEntIfIndex) being associated to |
1da177e4 LT |
2153 | the first interface found with a given IP address. That is, there is |
2154 | only one ipAdEntIfIndex for each IP address. For example, if eth0 and | |
2155 | eth1 are slaves of bond0 and the driver for eth0 is loaded before the | |
2156 | bonding driver, the interface for the IP address will be associated | |
2157 | with the eth0 interface. This configuration is shown below, the IP | |
2158 | address 192.168.1.1 has an interface index of 2 which indexes to eth0 | |
2159 | in the ifDescr table (ifDescr.2). | |
2160 | ||
a362032e MCC |
2161 | :: |
2162 | ||
1da177e4 LT |
2163 | interfaces.ifTable.ifEntry.ifDescr.1 = lo |
2164 | interfaces.ifTable.ifEntry.ifDescr.2 = eth0 | |
2165 | interfaces.ifTable.ifEntry.ifDescr.3 = eth1 | |
2166 | interfaces.ifTable.ifEntry.ifDescr.4 = eth2 | |
2167 | interfaces.ifTable.ifEntry.ifDescr.5 = eth3 | |
2168 | interfaces.ifTable.ifEntry.ifDescr.6 = bond0 | |
2169 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 5 | |
2170 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 | |
2171 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 4 | |
2172 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 | |
2173 | ||
a362032e | 2174 | This problem is avoided by loading the bonding driver before |
1da177e4 LT |
2175 | any network drivers participating in a bond. Below is an example of |
2176 | loading the bonding driver first, the IP address 192.168.1.1 is | |
2177 | correctly associated with ifDescr.2. | |
2178 | ||
2179 | interfaces.ifTable.ifEntry.ifDescr.1 = lo | |
2180 | interfaces.ifTable.ifEntry.ifDescr.2 = bond0 | |
2181 | interfaces.ifTable.ifEntry.ifDescr.3 = eth0 | |
2182 | interfaces.ifTable.ifEntry.ifDescr.4 = eth1 | |
2183 | interfaces.ifTable.ifEntry.ifDescr.5 = eth2 | |
2184 | interfaces.ifTable.ifEntry.ifDescr.6 = eth3 | |
2185 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.10.10.10 = 6 | |
2186 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.1.1 = 2 | |
2187 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.10.74.20.94 = 5 | |
2188 | ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 | |
2189 | ||
a362032e | 2190 | While some distributions may not report the interface name in |
1da177e4 LT |
2191 | ifDescr, the association between the IP address and IfIndex remains |
2192 | and SNMP functions such as Interface_Scan_Next will report that | |
2193 | association. | |
2194 | ||
6224e01d | 2195 | 10. Promiscuous mode |
1da177e4 LT |
2196 | ==================== |
2197 | ||
a362032e | 2198 | When running network monitoring tools, e.g., tcpdump, it is |
1da177e4 LT |
2199 | common to enable promiscuous mode on the device, so that all traffic |
2200 | is seen (instead of seeing only traffic destined for the local host). | |
2201 | The bonding driver handles promiscuous mode changes to the bonding | |
00354cfb | 2202 | master device (e.g., bond0), and propagates the setting to the slave |
1da177e4 LT |
2203 | devices. |
2204 | ||
a362032e | 2205 | For the balance-rr, balance-xor, broadcast, and 802.3ad modes, |
00354cfb | 2206 | the promiscuous mode setting is propagated to all slaves. |
1da177e4 | 2207 | |
a362032e | 2208 | For the active-backup, balance-tlb and balance-alb modes, the |
00354cfb | 2209 | promiscuous mode setting is propagated only to the active slave. |
1da177e4 | 2210 | |
a362032e | 2211 | For balance-tlb mode, the active slave is the slave currently |
1da177e4 LT |
2212 | receiving inbound traffic. |
2213 | ||
a362032e | 2214 | For balance-alb mode, the active slave is the slave used as a |
1da177e4 LT |
2215 | "primary." This slave is used for mode-specific control traffic, for |
2216 | sending to peers that are unassigned or if the load is unbalanced. | |
2217 | ||
a362032e | 2218 | For the active-backup, balance-tlb and balance-alb modes, when |
1da177e4 | 2219 | the active slave changes (e.g., due to a link failure), the |
00354cfb | 2220 | promiscuous setting will be propagated to the new active slave. |
1da177e4 | 2221 | |
6224e01d | 2222 | 11. Configuring Bonding for High Availability |
00354cfb | 2223 | ============================================= |
1da177e4 | 2224 | |
a362032e | 2225 | High Availability refers to configurations that provide |
1da177e4 | 2226 | maximum network availability by having redundant or backup devices, |
00354cfb JV |
2227 | links or switches between the host and the rest of the world. The |
2228 | goal is to provide the maximum availability of network connectivity | |
2229 | (i.e., the network always works), even though other configurations | |
2230 | could provide higher throughput. | |
1da177e4 | 2231 | |
6224e01d | 2232 | 11.1 High Availability in a Single Switch Topology |
1da177e4 LT |
2233 | -------------------------------------------------- |
2234 | ||
a362032e | 2235 | If two hosts (or a host and a single switch) are directly |
00354cfb JV |
2236 | connected via multiple physical links, then there is no availability |
2237 | penalty to optimizing for maximum bandwidth. In this case, there is | |
2238 | only one switch (or peer), so if it fails, there is no alternative | |
2239 | access to fail over to. Additionally, the bonding load balance modes | |
2240 | support link monitoring of their members, so if individual links fail, | |
2241 | the load will be rebalanced across the remaining devices. | |
2242 | ||
a362032e | 2243 | See Section 12, "Configuring Bonding for Maximum Throughput" |
00354cfb JV |
2244 | for information on configuring bonding with one peer device. |
2245 | ||
6224e01d | 2246 | 11.2 High Availability in a Multiple Switch Topology |
00354cfb JV |
2247 | ---------------------------------------------------- |
2248 | ||
a362032e | 2249 | With multiple switches, the configuration of bonding and the |
00354cfb JV |
2250 | network changes dramatically. In multiple switch topologies, there is |
2251 | a trade off between network availability and usable bandwidth. | |
2252 | ||
a362032e MCC |
2253 | Below is a sample network, configured to maximize the |
2254 | availability of the network:: | |
2255 | ||
2256 | | | | |
2257 | |port3 port3| | |
2258 | +-----+----+ +-----+----+ | |
2259 | | |port2 ISL port2| | | |
2260 | | switch A +--------------------------+ switch B | | |
2261 | | | | | | |
2262 | +-----+----+ +-----++---+ | |
2263 | |port1 port1| | |
2264 | | +-------+ | | |
2265 | +-------------+ host1 +---------------+ | |
2266 | eth0 +-------+ eth1 | |
2267 | ||
2268 | In this configuration, there is a link between the two | |
00354cfb JV |
2269 | switches (ISL, or inter switch link), and multiple ports connecting to |
2270 | the outside world ("port3" on each switch). There is no technical | |
2271 | reason that this could not be extended to a third switch. | |
1da177e4 | 2272 | |
6224e01d | 2273 | 11.2.1 HA Bonding Mode Selection for Multiple Switch Topology |
00354cfb | 2274 | ------------------------------------------------------------- |
1da177e4 | 2275 | |
a362032e | 2276 | In a topology such as the example above, the active-backup and |
00354cfb JV |
2277 | broadcast modes are the only useful bonding modes when optimizing for |
2278 | availability; the other modes require all links to terminate on the | |
2279 | same peer for them to behave rationally. | |
2280 | ||
a362032e MCC |
2281 | active-backup: |
2282 | This is generally the preferred mode, particularly if | |
00354cfb JV |
2283 | the switches have an ISL and play together well. If the |
2284 | network configuration is such that one switch is specifically | |
2285 | a backup switch (e.g., has lower capacity, higher cost, etc), | |
2286 | then the primary option can be used to insure that the | |
2287 | preferred link is always used when it is available. | |
2288 | ||
a362032e MCC |
2289 | broadcast: |
2290 | This mode is really a special purpose mode, and is suitable | |
00354cfb JV |
2291 | only for very specific needs. For example, if the two |
2292 | switches are not connected (no ISL), and the networks beyond | |
2293 | them are totally independent. In this case, if it is | |
2294 | necessary for some specific one-way traffic to reach both | |
2295 | independent networks, then the broadcast mode may be suitable. | |
2296 | ||
6224e01d | 2297 | 11.2.2 HA Link Monitoring Selection for Multiple Switch Topology |
00354cfb JV |
2298 | ---------------------------------------------------------------- |
2299 | ||
a362032e | 2300 | The choice of link monitoring ultimately depends upon your |
00354cfb JV |
2301 | switch. If the switch can reliably fail ports in response to other |
2302 | failures, then either the MII or ARP monitors should work. For | |
2303 | example, in the above example, if the "port3" link fails at the remote | |
2304 | end, the MII monitor has no direct means to detect this. The ARP | |
2305 | monitor could be configured with a target at the remote end of port3, | |
2306 | thus detecting that failure without switch support. | |
2307 | ||
a362032e | 2308 | In general, however, in a multiple switch topology, the ARP |
00354cfb JV |
2309 | monitor can provide a higher level of reliability in detecting end to |
2310 | end connectivity failures (which may be caused by the failure of any | |
2311 | individual component to pass traffic for any reason). Additionally, | |
2312 | the ARP monitor should be configured with multiple targets (at least | |
2313 | one for each switch in the network). This will insure that, | |
2314 | regardless of which switch is active, the ARP monitor has a suitable | |
2315 | target to query. | |
2316 | ||
a362032e | 2317 | Note, also, that of late many switches now support a functionality |
9a6c6867 JV |
2318 | generally referred to as "trunk failover." This is a feature of the |
2319 | switch that causes the link state of a particular switch port to be set | |
2320 | down (or up) when the state of another switch port goes down (or up). | |
19f59460 | 2321 | Its purpose is to propagate link failures from logically "exterior" ports |
9a6c6867 JV |
2322 | to the logically "interior" ports that bonding is able to monitor via |
2323 | miimon. Availability and configuration for trunk failover varies by | |
2324 | switch, but this can be a viable alternative to the ARP monitor when using | |
2325 | suitable switches. | |
00354cfb | 2326 | |
6224e01d | 2327 | 12. Configuring Bonding for Maximum Throughput |
00354cfb JV |
2328 | ============================================== |
2329 | ||
6224e01d | 2330 | 12.1 Maximizing Throughput in a Single Switch Topology |
00354cfb JV |
2331 | ------------------------------------------------------ |
2332 | ||
a362032e | 2333 | In a single switch configuration, the best method to maximize |
00354cfb JV |
2334 | throughput depends upon the application and network environment. The |
2335 | various load balancing modes each have strengths and weaknesses in | |
2336 | different environments, as detailed below. | |
2337 | ||
a362032e | 2338 | For this discussion, we will break down the topologies into |
00354cfb JV |
2339 | two categories. Depending upon the destination of most traffic, we |
2340 | categorize them into either "gatewayed" or "local" configurations. | |
2341 | ||
a362032e | 2342 | In a gatewayed configuration, the "switch" is acting primarily |
00354cfb | 2343 | as a router, and the majority of traffic passes through this router to |
a362032e | 2344 | other networks. An example would be the following:: |
00354cfb JV |
2345 | |
2346 | ||
2347 | +----------+ +----------+ | |
2348 | | |eth0 port1| | to other networks | |
2349 | | Host A +---------------------+ router +-------------------> | |
2350 | | +---------------------+ | Hosts B and C are out | |
2351 | | |eth1 port2| | here somewhere | |
2352 | +----------+ +----------+ | |
2353 | ||
a362032e | 2354 | The router may be a dedicated router device, or another host |
00354cfb JV |
2355 | acting as a gateway. For our discussion, the important point is that |
2356 | the majority of traffic from Host A will pass through the router to | |
2357 | some other network before reaching its final destination. | |
2358 | ||
a362032e | 2359 | In a gatewayed network configuration, although Host A may |
00354cfb JV |
2360 | communicate with many other systems, all of its traffic will be sent |
2361 | and received via one other peer on the local network, the router. | |
2362 | ||
a362032e | 2363 | Note that the case of two systems connected directly via |
00354cfb JV |
2364 | multiple physical links is, for purposes of configuring bonding, the |
2365 | same as a gatewayed configuration. In that case, it happens that all | |
2366 | traffic is destined for the "gateway" itself, not some other network | |
2367 | beyond the gateway. | |
2368 | ||
a362032e | 2369 | In a local configuration, the "switch" is acting primarily as |
00354cfb JV |
2370 | a switch, and the majority of traffic passes through this switch to |
2371 | reach other stations on the same network. An example would be the | |
a362032e | 2372 | following:: |
00354cfb JV |
2373 | |
2374 | +----------+ +----------+ +--------+ | |
2375 | | |eth0 port1| +-------+ Host B | | |
2376 | | Host A +------------+ switch |port3 +--------+ | |
2377 | | +------------+ | +--------+ | |
2378 | | |eth1 port2| +------------------+ Host C | | |
2379 | +----------+ +----------+port4 +--------+ | |
2380 | ||
2381 | ||
a362032e | 2382 | Again, the switch may be a dedicated switch device, or another |
00354cfb JV |
2383 | host acting as a gateway. For our discussion, the important point is |
2384 | that the majority of traffic from Host A is destined for other hosts | |
2385 | on the same local network (Hosts B and C in the above example). | |
2386 | ||
a362032e | 2387 | In summary, in a gatewayed configuration, traffic to and from |
00354cfb JV |
2388 | the bonded device will be to the same MAC level peer on the network |
2389 | (the gateway itself, i.e., the router), regardless of its final | |
2390 | destination. In a local configuration, traffic flows directly to and | |
2391 | from the final destinations, thus, each destination (Host B, Host C) | |
2392 | will be addressed directly by their individual MAC addresses. | |
2393 | ||
a362032e | 2394 | This distinction between a gatewayed and a local network |
00354cfb JV |
2395 | configuration is important because many of the load balancing modes |
2396 | available use the MAC addresses of the local network source and | |
2397 | destination to make load balancing decisions. The behavior of each | |
2398 | mode is described below. | |
2399 | ||
2400 | ||
6224e01d | 2401 | 12.1.1 MT Bonding Mode Selection for Single Switch Topology |
00354cfb | 2402 | ----------------------------------------------------------- |
1da177e4 | 2403 | |
a362032e | 2404 | This configuration is the easiest to set up and to understand, |
1da177e4 | 2405 | although you will have to decide which bonding mode best suits your |
00354cfb | 2406 | needs. The trade offs for each mode are detailed below: |
1da177e4 | 2407 | |
a362032e MCC |
2408 | balance-rr: |
2409 | This mode is the only mode that will permit a single | |
1da177e4 LT |
2410 | TCP/IP connection to stripe traffic across multiple |
2411 | interfaces. It is therefore the only mode that will allow a | |
2412 | single TCP/IP stream to utilize more than one interface's | |
2413 | worth of throughput. This comes at a cost, however: the | |
9a6c6867 | 2414 | striping generally results in peer systems receiving packets out |
1da177e4 LT |
2415 | of order, causing TCP/IP's congestion control system to kick |
2416 | in, often by retransmitting segments. | |
2417 | ||
2418 | It is possible to adjust TCP/IP's congestion limits by | |
2419 | altering the net.ipv4.tcp_reordering sysctl parameter. The | |
dca145ff ED |
2420 | usual default value is 3. But keep in mind TCP stack is able |
2421 | to automatically increase this when it detects reorders. | |
1da177e4 | 2422 | |
9a6c6867 JV |
2423 | Note that the fraction of packets that will be delivered out of |
2424 | order is highly variable, and is unlikely to be zero. The level | |
2425 | of reordering depends upon a variety of factors, including the | |
2426 | networking interfaces, the switch, and the topology of the | |
2427 | configuration. Speaking in general terms, higher speed network | |
2428 | cards produce more reordering (due to factors such as packet | |
2429 | coalescing), and a "many to many" topology will reorder at a | |
2430 | higher rate than a "many slow to one fast" configuration. | |
2431 | ||
2432 | Many switches do not support any modes that stripe traffic | |
2433 | (instead choosing a port based upon IP or MAC level addresses); | |
2434 | for those devices, traffic for a particular connection flowing | |
2435 | through the switch to a balance-rr bond will not utilize greater | |
2436 | than one interface's worth of bandwidth. | |
00354cfb | 2437 | |
1da177e4 LT |
2438 | If you are utilizing protocols other than TCP/IP, UDP for |
2439 | example, and your application can tolerate out of order | |
2440 | delivery, then this mode can allow for single stream datagram | |
2441 | performance that scales near linearly as interfaces are added | |
2442 | to the bond. | |
2443 | ||
2444 | This mode requires the switch to have the appropriate ports | |
2445 | configured for "etherchannel" or "trunking." | |
2446 | ||
a362032e MCC |
2447 | active-backup: |
2448 | There is not much advantage in this network topology to | |
1da177e4 LT |
2449 | the active-backup mode, as the inactive backup devices are all |
2450 | connected to the same peer as the primary. In this case, a | |
2451 | load balancing mode (with link monitoring) will provide the | |
2452 | same level of network availability, but with increased | |
00354cfb JV |
2453 | available bandwidth. On the plus side, active-backup mode |
2454 | does not require any configuration of the switch, so it may | |
2455 | have value if the hardware available does not support any of | |
2456 | the load balance modes. | |
1da177e4 | 2457 | |
a362032e MCC |
2458 | balance-xor: |
2459 | This mode will limit traffic such that packets destined | |
1da177e4 LT |
2460 | for specific peers will always be sent over the same |
2461 | interface. Since the destination is determined by the MAC | |
00354cfb JV |
2462 | addresses involved, this mode works best in a "local" network |
2463 | configuration (as described above), with destinations all on | |
2464 | the same local network. This mode is likely to be suboptimal | |
2465 | if all your traffic is passed through a single router (i.e., a | |
2466 | "gatewayed" network configuration, as described above). | |
2467 | ||
2468 | As with balance-rr, the switch ports need to be configured for | |
1da177e4 LT |
2469 | "etherchannel" or "trunking." |
2470 | ||
a362032e MCC |
2471 | broadcast: |
2472 | Like active-backup, there is not much advantage to this | |
1da177e4 LT |
2473 | mode in this type of network topology. |
2474 | ||
a362032e MCC |
2475 | 802.3ad: |
2476 | This mode can be a good choice for this type of network | |
1da177e4 LT |
2477 | topology. The 802.3ad mode is an IEEE standard, so all peers |
2478 | that implement 802.3ad should interoperate well. The 802.3ad | |
2479 | protocol includes automatic configuration of the aggregates, | |
2480 | so minimal manual configuration of the switch is needed | |
2481 | (typically only to designate that some set of devices is | |
00354cfb JV |
2482 | available for 802.3ad). The 802.3ad standard also mandates |
2483 | that frames be delivered in order (within certain limits), so | |
2484 | in general single connections will not see misordering of | |
1da177e4 LT |
2485 | packets. The 802.3ad mode does have some drawbacks: the |
2486 | standard mandates that all devices in the aggregate operate at | |
2487 | the same speed and duplex. Also, as with all bonding load | |
2488 | balance modes other than balance-rr, no single connection will | |
2489 | be able to utilize more than a single interface's worth of | |
a362032e | 2490 | bandwidth. |
00354cfb JV |
2491 | |
2492 | Additionally, the linux bonding 802.3ad implementation | |
92abf750 JX |
2493 | distributes traffic by peer (using an XOR of MAC addresses |
2494 | and packet type ID), so in a "gatewayed" configuration, all | |
2495 | outgoing traffic will generally use the same device. Incoming | |
2496 | traffic may also end up on a single device, but that is | |
00a534e5 | 2497 | dependent upon the balancing policy of the peer's 802.3ad |
92abf750 JX |
2498 | implementation. In a "local" configuration, traffic will be |
2499 | distributed across the devices in the bond. | |
00354cfb JV |
2500 | |
2501 | Finally, the 802.3ad mode mandates the use of the MII monitor, | |
2502 | therefore, the ARP monitor is not available in this mode. | |
2503 | ||
a362032e MCC |
2504 | balance-tlb: |
2505 | The balance-tlb mode balances outgoing traffic by peer. | |
00354cfb JV |
2506 | Since the balancing is done according to MAC address, in a |
2507 | "gatewayed" configuration (as described above), this mode will | |
2508 | send all traffic across a single device. However, in a | |
2509 | "local" network configuration, this mode balances multiple | |
2510 | local network peers across devices in a vaguely intelligent | |
2511 | manner (not a simple XOR as in balance-xor or 802.3ad mode), | |
2512 | so that mathematically unlucky MAC addresses (i.e., ones that | |
2513 | XOR to the same value) will not all "bunch up" on a single | |
2514 | interface. | |
2515 | ||
2516 | Unlike 802.3ad, interfaces may be of differing speeds, and no | |
2517 | special switch configuration is required. On the down side, | |
2518 | in this mode all incoming traffic arrives over a single | |
2519 | interface, this mode requires certain ethtool support in the | |
2520 | network device driver of the slave interfaces, and the ARP | |
2521 | monitor is not available. | |
2522 | ||
a362032e MCC |
2523 | balance-alb: |
2524 | This mode is everything that balance-tlb is, and more. | |
00354cfb JV |
2525 | It has all of the features (and restrictions) of balance-tlb, |
2526 | and will also balance incoming traffic from local network | |
2527 | peers (as described in the Bonding Module Options section, | |
2528 | above). | |
2529 | ||
2530 | The only additional down side to this mode is that the network | |
2531 | device driver must support changing the hardware address while | |
2532 | the device is open. | |
2533 | ||
6224e01d | 2534 | 12.1.2 MT Link Monitoring for Single Switch Topology |
00354cfb | 2535 | ---------------------------------------------------- |
1da177e4 | 2536 | |
a362032e | 2537 | The choice of link monitoring may largely depend upon which |
1da177e4 LT |
2538 | mode you choose to use. The more advanced load balancing modes do not |
2539 | support the use of the ARP monitor, and are thus restricted to using | |
00354cfb JV |
2540 | the MII monitor (which does not provide as high a level of end to end |
2541 | assurance as the ARP monitor). | |
2542 | ||
6224e01d | 2543 | 12.2 Maximum Throughput in a Multiple Switch Topology |
00354cfb JV |
2544 | ----------------------------------------------------- |
2545 | ||
a362032e | 2546 | Multiple switches may be utilized to optimize for throughput |
00354cfb | 2547 | when they are configured in parallel as part of an isolated network |
a362032e MCC |
2548 | between two or more systems, for example:: |
2549 | ||
2550 | +-----------+ | |
2551 | | Host A | | |
2552 | +-+---+---+-+ | |
2553 | | | | | |
2554 | +--------+ | +---------+ | |
2555 | | | | | |
2556 | +------+---+ +-----+----+ +-----+----+ | |
2557 | | Switch A | | Switch B | | Switch C | | |
2558 | +------+---+ +-----+----+ +-----+----+ | |
2559 | | | | | |
2560 | +--------+ | +---------+ | |
2561 | | | | | |
2562 | +-+---+---+-+ | |
2563 | | Host B | | |
2564 | +-----------+ | |
2565 | ||
2566 | In this configuration, the switches are isolated from one | |
00354cfb JV |
2567 | another. One reason to employ a topology such as this is for an |
2568 | isolated network with many hosts (a cluster configured for high | |
2569 | performance, for example), using multiple smaller switches can be more | |
2570 | cost effective than a single larger switch, e.g., on a network with 24 | |
2571 | hosts, three 24 port switches can be significantly less expensive than | |
2572 | a single 72 port switch. | |
2573 | ||
a362032e | 2574 | If access beyond the network is required, an individual host |
00354cfb JV |
2575 | can be equipped with an additional network device connected to an |
2576 | external network; this host then additionally acts as a gateway. | |
2577 | ||
6224e01d | 2578 | 12.2.1 MT Bonding Mode Selection for Multiple Switch Topology |
1da177e4 LT |
2579 | ------------------------------------------------------------- |
2580 | ||
a362032e | 2581 | In actual practice, the bonding mode typically employed in |
00354cfb JV |
2582 | configurations of this type is balance-rr. Historically, in this |
2583 | network configuration, the usual caveats about out of order packet | |
2584 | delivery are mitigated by the use of network adapters that do not do | |
2585 | any kind of packet coalescing (via the use of NAPI, or because the | |
2586 | device itself does not generate interrupts until some number of | |
2587 | packets has arrived). When employed in this fashion, the balance-rr | |
2588 | mode allows individual connections between two hosts to effectively | |
2589 | utilize greater than one interface's bandwidth. | |
1da177e4 | 2590 | |
6224e01d | 2591 | 12.2.2 MT Link Monitoring for Multiple Switch Topology |
00354cfb | 2592 | ------------------------------------------------------ |
1da177e4 | 2593 | |
a362032e | 2594 | Again, in actual practice, the MII monitor is most often used |
00354cfb JV |
2595 | in this configuration, as performance is given preference over |
2596 | availability. The ARP monitor will function in this topology, but its | |
2597 | advantages over the MII monitor are mitigated by the volume of probes | |
2598 | needed as the number of systems involved grows (remember that each | |
2599 | host in the network is configured with bonding). | |
1da177e4 | 2600 | |
6224e01d | 2601 | 13. Switch Behavior Issues |
00354cfb | 2602 | ========================== |
1da177e4 | 2603 | |
6224e01d | 2604 | 13.1 Link Establishment and Failover Delays |
00354cfb JV |
2605 | ------------------------------------------- |
2606 | ||
a362032e | 2607 | Some switches exhibit undesirable behavior with regard to the |
00354cfb | 2608 | timing of link up and down reporting by the switch. |
1da177e4 | 2609 | |
a362032e | 2610 | First, when a link comes up, some switches may indicate that |
1da177e4 LT |
2611 | the link is up (carrier available), but not pass traffic over the |
2612 | interface for some period of time. This delay is typically due to | |
2613 | some type of autonegotiation or routing protocol, but may also occur | |
2614 | during switch initialization (e.g., during recovery after a switch | |
2615 | failure). If you find this to be a problem, specify an appropriate | |
2616 | value to the updelay bonding module option to delay the use of the | |
2617 | relevant interface(s). | |
2618 | ||
a362032e | 2619 | Second, some switches may "bounce" the link state one or more |
1da177e4 LT |
2620 | times while a link is changing state. This occurs most commonly while |
2621 | the switch is initializing. Again, an appropriate updelay value may | |
00354cfb | 2622 | help. |
1da177e4 | 2623 | |
a362032e | 2624 | Note that when a bonding interface has no active links, the |
00354cfb JV |
2625 | driver will immediately reuse the first link that goes up, even if the |
2626 | updelay parameter has been specified (the updelay is ignored in this | |
2627 | case). If there are slave interfaces waiting for the updelay timeout | |
2628 | to expire, the interface that first went into that state will be | |
2629 | immediately reused. This reduces down time of the network if the | |
2630 | value of updelay has been overestimated, and since this occurs only in | |
2631 | cases with no connectivity, there is no additional penalty for | |
2632 | ignoring the updelay. | |
1da177e4 | 2633 | |
a362032e | 2634 | In addition to the concerns about switch timings, if your |
1da177e4 LT |
2635 | switches take a long time to go into backup mode, it may be desirable |
2636 | to not activate a backup interface immediately after a link goes down. | |
2637 | Failover may be delayed via the downdelay bonding module option. | |
2638 | ||
6224e01d | 2639 | 13.2 Duplicated Incoming Packets |
00354cfb JV |
2640 | -------------------------------- |
2641 | ||
a362032e | 2642 | NOTE: Starting with version 3.0.2, the bonding driver has logic to |
9a6c6867 JV |
2643 | suppress duplicate packets, which should largely eliminate this problem. |
2644 | The following description is kept for reference. | |
2645 | ||
a362032e | 2646 | It is not uncommon to observe a short burst of duplicated |
00354cfb JV |
2647 | traffic when the bonding device is first used, or after it has been |
2648 | idle for some period of time. This is most easily observed by issuing | |
2649 | a "ping" to some other host on the network, and noticing that the | |
2650 | output from ping flags duplicates (typically one per slave). | |
2651 | ||
a362032e MCC |
2652 | For example, on a bond in active-backup mode with five slaves |
2653 | all connected to one switch, the output may appear as follows:: | |
2654 | ||
2655 | # ping -n 10.0.4.2 | |
2656 | PING 10.0.4.2 (10.0.4.2) from 10.0.3.10 : 56(84) bytes of data. | |
2657 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.7 ms | |
2658 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2659 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2660 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2661 | 64 bytes from 10.0.4.2: icmp_seq=1 ttl=64 time=13.8 ms (DUP!) | |
2662 | 64 bytes from 10.0.4.2: icmp_seq=2 ttl=64 time=0.216 ms | |
2663 | 64 bytes from 10.0.4.2: icmp_seq=3 ttl=64 time=0.267 ms | |
2664 | 64 bytes from 10.0.4.2: icmp_seq=4 ttl=64 time=0.222 ms | |
2665 | ||
2666 | This is not due to an error in the bonding driver, rather, it | |
00354cfb JV |
2667 | is a side effect of how many switches update their MAC forwarding |
2668 | tables. Initially, the switch does not associate the MAC address in | |
2669 | the packet with a particular switch port, and so it may send the | |
2670 | traffic to all ports until its MAC forwarding table is updated. Since | |
2671 | the interfaces attached to the bond may occupy multiple ports on a | |
2672 | single switch, when the switch (temporarily) floods the traffic to all | |
2673 | ports, the bond device receives multiple copies of the same packet | |
2674 | (one per slave device). | |
2675 | ||
a362032e | 2676 | The duplicated packet behavior is switch dependent, some |
00354cfb JV |
2677 | switches exhibit this, and some do not. On switches that display this |
2678 | behavior, it can be induced by clearing the MAC forwarding table (on | |
2679 | most Cisco switches, the privileged command "clear mac address-table | |
2680 | dynamic" will accomplish this). | |
2681 | ||
6224e01d | 2682 | 14. Hardware Specific Considerations |
1da177e4 LT |
2683 | ==================================== |
2684 | ||
a362032e | 2685 | This section contains additional information for configuring |
1da177e4 LT |
2686 | bonding on specific hardware platforms, or for interfacing bonding |
2687 | with particular switches or other devices. | |
2688 | ||
6224e01d | 2689 | 14.1 IBM BladeCenter |
1da177e4 LT |
2690 | -------------------- |
2691 | ||
a362032e | 2692 | This applies to the JS20 and similar systems. |
1da177e4 | 2693 | |
a362032e | 2694 | On the JS20 blades, the bonding driver supports only |
1da177e4 LT |
2695 | balance-rr, active-backup, balance-tlb and balance-alb modes. This is |
2696 | largely due to the network topology inside the BladeCenter, detailed | |
2697 | below. | |
2698 | ||
2699 | JS20 network adapter information | |
2700 | -------------------------------- | |
2701 | ||
a362032e | 2702 | All JS20s come with two Broadcom Gigabit Ethernet ports |
00354cfb JV |
2703 | integrated on the planar (that's "motherboard" in IBM-speak). In the |
2704 | BladeCenter chassis, the eth0 port of all JS20 blades is hard wired to | |
2705 | I/O Module #1; similarly, all eth1 ports are wired to I/O Module #2. | |
2706 | An add-on Broadcom daughter card can be installed on a JS20 to provide | |
2707 | two more Gigabit Ethernet ports. These ports, eth2 and eth3, are | |
2708 | wired to I/O Modules 3 and 4, respectively. | |
1da177e4 | 2709 | |
a362032e | 2710 | Each I/O Module may contain either a switch or a passthrough |
1da177e4 LT |
2711 | module (which allows ports to be directly connected to an external |
2712 | switch). Some bonding modes require a specific BladeCenter internal | |
2713 | network topology in order to function; these are detailed below. | |
2714 | ||
a362032e | 2715 | Additional BladeCenter-specific networking information can be |
1da177e4 LT |
2716 | found in two IBM Redbooks (www.ibm.com/redbooks): |
2717 | ||
a362032e MCC |
2718 | - "IBM eServer BladeCenter Networking Options" |
2719 | - "IBM eServer BladeCenter Layer 2-7 Network Switching" | |
1da177e4 LT |
2720 | |
2721 | BladeCenter networking configuration | |
2722 | ------------------------------------ | |
2723 | ||
a362032e | 2724 | Because a BladeCenter can be configured in a very large number |
1da177e4 LT |
2725 | of ways, this discussion will be confined to describing basic |
2726 | configurations. | |
2727 | ||
a362032e | 2728 | Normally, Ethernet Switch Modules (ESMs) are used in I/O |
1da177e4 LT |
2729 | modules 1 and 2. In this configuration, the eth0 and eth1 ports of a |
2730 | JS20 will be connected to different internal switches (in the | |
2731 | respective I/O modules). | |
2732 | ||
a362032e | 2733 | A passthrough module (OPM or CPM, optical or copper, |
00354cfb JV |
2734 | passthrough module) connects the I/O module directly to an external |
2735 | switch. By using PMs in I/O module #1 and #2, the eth0 and eth1 | |
2736 | interfaces of a JS20 can be redirected to the outside world and | |
2737 | connected to a common external switch. | |
2738 | ||
a362032e | 2739 | Depending upon the mix of ESMs and PMs, the network will |
00354cfb JV |
2740 | appear to bonding as either a single switch topology (all PMs) or as a |
2741 | multiple switch topology (one or more ESMs, zero or more PMs). It is | |
2742 | also possible to connect ESMs together, resulting in a configuration | |
2743 | much like the example in "High Availability in a Multiple Switch | |
2744 | Topology," above. | |
2745 | ||
2746 | Requirements for specific modes | |
2747 | ------------------------------- | |
2748 | ||
a362032e | 2749 | The balance-rr mode requires the use of passthrough modules |
00354cfb JV |
2750 | for devices in the bond, all connected to an common external switch. |
2751 | That switch must be configured for "etherchannel" or "trunking" on the | |
1da177e4 LT |
2752 | appropriate ports, as is usual for balance-rr. |
2753 | ||
a362032e | 2754 | The balance-alb and balance-tlb modes will function with |
1da177e4 LT |
2755 | either switch modules or passthrough modules (or a mix). The only |
2756 | specific requirement for these modes is that all network interfaces | |
2757 | must be able to reach all destinations for traffic sent over the | |
2758 | bonding device (i.e., the network must converge at some point outside | |
2759 | the BladeCenter). | |
2760 | ||
a362032e | 2761 | The active-backup mode has no additional requirements. |
1da177e4 LT |
2762 | |
2763 | Link monitoring issues | |
2764 | ---------------------- | |
2765 | ||
a362032e | 2766 | When an Ethernet Switch Module is in place, only the ARP |
1da177e4 LT |
2767 | monitor will reliably detect link loss to an external switch. This is |
2768 | nothing unusual, but examination of the BladeCenter cabinet would | |
2769 | suggest that the "external" network ports are the ethernet ports for | |
2770 | the system, when it fact there is a switch between these "external" | |
2771 | ports and the devices on the JS20 system itself. The MII monitor is | |
2772 | only able to detect link failures between the ESM and the JS20 system. | |
2773 | ||
a362032e | 2774 | When a passthrough module is in place, the MII monitor does |
1da177e4 LT |
2775 | detect failures to the "external" port, which is then directly |
2776 | connected to the JS20 system. | |
2777 | ||
2778 | Other concerns | |
2779 | -------------- | |
2780 | ||
a362032e | 2781 | The Serial Over LAN (SoL) link is established over the primary |
1da177e4 LT |
2782 | ethernet (eth0) only, therefore, any loss of link to eth0 will result |
2783 | in losing your SoL connection. It will not fail over with other | |
00354cfb JV |
2784 | network traffic, as the SoL system is beyond the control of the |
2785 | bonding driver. | |
1da177e4 | 2786 | |
a362032e | 2787 | It may be desirable to disable spanning tree on the switch |
1da177e4 | 2788 | (either the internal Ethernet Switch Module, or an external switch) to |
00354cfb | 2789 | avoid fail-over delay issues when using bonding. |
1da177e4 | 2790 | |
a362032e | 2791 | |
6224e01d | 2792 | 15. Frequently Asked Questions |
1da177e4 LT |
2793 | ============================== |
2794 | ||
2795 | 1. Is it SMP safe? | |
a362032e | 2796 | ------------------- |
1da177e4 | 2797 | |
a362032e | 2798 | Yes. The old 2.0.xx channel bonding patch was not SMP safe. |
1da177e4 LT |
2799 | The new driver was designed to be SMP safe from the start. |
2800 | ||
2801 | 2. What type of cards will work with it? | |
a362032e | 2802 | ----------------------------------------- |
1da177e4 | 2803 | |
a362032e | 2804 | Any Ethernet type cards (you can even mix cards - a Intel |
00354cfb JV |
2805 | EtherExpress PRO/100 and a 3com 3c905b, for example). For most modes, |
2806 | devices need not be of the same speed. | |
1da177e4 | 2807 | |
a362032e | 2808 | Starting with version 3.2.1, bonding also supports Infiniband |
9a6c6867 JV |
2809 | slaves in active-backup mode. |
2810 | ||
1da177e4 | 2811 | 3. How many bonding devices can I have? |
a362032e | 2812 | ---------------------------------------- |
1da177e4 | 2813 | |
a362032e | 2814 | There is no limit. |
1da177e4 LT |
2815 | |
2816 | 4. How many slaves can a bonding device have? | |
a362032e | 2817 | ---------------------------------------------- |
1da177e4 | 2818 | |
a362032e | 2819 | This is limited only by the number of network interfaces Linux |
1da177e4 LT |
2820 | supports and/or the number of network cards you can place in your |
2821 | system. | |
2822 | ||
2823 | 5. What happens when a slave link dies? | |
a362032e | 2824 | ---------------------------------------- |
1da177e4 | 2825 | |
a362032e | 2826 | If link monitoring is enabled, then the failing device will be |
1da177e4 LT |
2827 | disabled. The active-backup mode will fail over to a backup link, and |
2828 | other modes will ignore the failed link. The link will continue to be | |
2829 | monitored, and should it recover, it will rejoin the bond (in whatever | |
00354cfb JV |
2830 | manner is appropriate for the mode). See the sections on High |
2831 | Availability and the documentation for each mode for additional | |
2832 | information. | |
a362032e MCC |
2833 | |
2834 | Link monitoring can be enabled via either the miimon or | |
00354cfb | 2835 | arp_interval parameters (described in the module parameters section, |
1da177e4 LT |
2836 | above). In general, miimon monitors the carrier state as sensed by |
2837 | the underlying network device, and the arp monitor (arp_interval) | |
2838 | monitors connectivity to another host on the local network. | |
2839 | ||
a362032e | 2840 | If no link monitoring is configured, the bonding driver will |
1da177e4 LT |
2841 | be unable to detect link failures, and will assume that all links are |
2842 | always available. This will likely result in lost packets, and a | |
00354cfb | 2843 | resulting degradation of performance. The precise performance loss |
1da177e4 LT |
2844 | depends upon the bonding mode and network configuration. |
2845 | ||
2846 | 6. Can bonding be used for High Availability? | |
a362032e | 2847 | ---------------------------------------------- |
1da177e4 | 2848 | |
a362032e | 2849 | Yes. See the section on High Availability for details. |
1da177e4 LT |
2850 | |
2851 | 7. Which switches/systems does it work with? | |
a362032e | 2852 | --------------------------------------------- |
1da177e4 | 2853 | |
a362032e | 2854 | The full answer to this depends upon the desired mode. |
1da177e4 | 2855 | |
a362032e | 2856 | In the basic balance modes (balance-rr and balance-xor), it |
1da177e4 LT |
2857 | works with any system that supports etherchannel (also called |
2858 | trunking). Most managed switches currently available have such | |
00354cfb | 2859 | support, and many unmanaged switches as well. |
1da177e4 | 2860 | |
a362032e | 2861 | The advanced balance modes (balance-tlb and balance-alb) do |
1da177e4 LT |
2862 | not have special switch requirements, but do need device drivers that |
2863 | support specific features (described in the appropriate section under | |
00354cfb | 2864 | module parameters, above). |
1da177e4 | 2865 | |
a362032e | 2866 | In 802.3ad mode, it works with systems that support IEEE |
1da177e4 LT |
2867 | 802.3ad Dynamic Link Aggregation. Most managed and many unmanaged |
2868 | switches currently available support 802.3ad. | |
2869 | ||
a362032e | 2870 | The active-backup mode should work with any Layer-II switch. |
1da177e4 LT |
2871 | |
2872 | 8. Where does a bonding device get its MAC address from? | |
a362032e | 2873 | --------------------------------------------------------- |
1da177e4 | 2874 | |
a362032e | 2875 | When using slave devices that have fixed MAC addresses, or when |
9a6c6867 JV |
2876 | the fail_over_mac option is enabled, the bonding device's MAC address is |
2877 | the MAC address of the active slave. | |
2878 | ||
a362032e | 2879 | For other configurations, if not explicitly configured (with |
9a6c6867 JV |
2880 | ifconfig or ip link), the MAC address of the bonding device is taken from |
2881 | its first slave device. This MAC address is then passed to all following | |
2882 | slaves and remains persistent (even if the first slave is removed) until | |
2883 | the bonding device is brought down or reconfigured. | |
1da177e4 | 2884 | |
a362032e MCC |
2885 | If you wish to change the MAC address, you can set it with |
2886 | ifconfig or ip link:: | |
1da177e4 | 2887 | |
a362032e | 2888 | # ifconfig bond0 hw ether 00:11:22:33:44:55 |
1da177e4 | 2889 | |
a362032e | 2890 | # ip link set bond0 address 66:77:88:99:aa:bb |
00354cfb | 2891 | |
a362032e MCC |
2892 | The MAC address can be also changed by bringing down/up the |
2893 | device and then changing its slaves (or their order):: | |
1da177e4 | 2894 | |
a362032e MCC |
2895 | # ifconfig bond0 down ; modprobe -r bonding |
2896 | # ifconfig bond0 .... up | |
2897 | # ifenslave bond0 eth... | |
1da177e4 | 2898 | |
a362032e | 2899 | This method will automatically take the address from the next |
1da177e4 LT |
2900 | slave that is added. |
2901 | ||
a362032e MCC |
2902 | To restore your slaves' MAC addresses, you need to detach them |
2903 | from the bond (``ifenslave -d bond0 eth0``). The bonding driver will | |
1da177e4 LT |
2904 | then restore the MAC addresses that the slaves had before they were |
2905 | enslaved. | |
2906 | ||
00354cfb | 2907 | 16. Resources and Links |
1da177e4 LT |
2908 | ======================= |
2909 | ||
a362032e | 2910 | The latest version of the bonding driver can be found in the latest |
1da177e4 LT |
2911 | version of the linux kernel, found on http://kernel.org |
2912 | ||
a362032e MCC |
2913 | The latest version of this document can be found in the latest kernel |
2914 | source (named Documentation/networking/bonding.rst). | |
00354cfb | 2915 | |
a362032e | 2916 | Discussions regarding the development of the bonding driver take place |
a23c37f1 NP |
2917 | on the main Linux network mailing list, hosted at vger.kernel.org. The list |
2918 | address is: | |
2919 | ||
2920 | netdev@vger.kernel.org | |
2921 | ||
a362032e | 2922 | The administrative interface (to subscribe or unsubscribe) can |
a23c37f1 NP |
2923 | be found at: |
2924 | ||
2925 | http://vger.kernel.org/vger-lists.html#netdev |