4 fio is a tool that will spawn a number of threads or processes doing a
5 particular type of io action as specified by the user. fio takes a
6 number of global parameters, each inherited by the thread unless
7 otherwise parameters given to them overriding that setting is given.
8 The typical use of fio is to write a job file matching the io load
15 fio resides in a git repo, the canonical place is:
17 git://git.kernel.dk/fio.git
19 If you are inside a corporate firewall, git:// may not always work for
20 you. In that case you can use the http protocol, path is the same:
22 http://git.kernel.dk/fio.git
24 Snapshots are frequently generated and they include the git meta data as
25 well. You can download them here:
27 http://brick.kernel.dk/snaps/
34 Starting with Debian "Squeeze", fio packages are part of the official
35 Debian repository. http://packages.debian.org/search?keywords=fio
38 Starting with Ubuntu 10.04 LTS (aka "Lucid Lynx"), fio packages are part
39 of the Ubuntu "universe" repository.
40 http://packages.ubuntu.com/search?keywords=fio
43 Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for SUSE
44 variants, you can find them here:
45 http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
48 Dag Wieƫrs has RPMs for Red Hat related distros, find them here:
49 http://dag.wieers.com/rpm/packages/fio/
52 Mandriva has integrated fio into their package repository, so installing
53 on that distro should be as easy as typing 'urpmi fio'.
56 Packages for Solaris are available from OpenCSW. Install their pkgutil
57 tool (http://www.opencsw.org/get-it/pkgutil/) and then install fio via
61 Bruce Cran <bruce@cran.org.uk> has fio packages for Windows at
62 http://www.bluestop.org/fio .
68 There's a mailing list associated with fio. It's meant for general
69 discussion, bug reporting, questions, and development - basically anything
70 that has to do with fio. An automated mail detailing recent commits is
71 automatically sent to the list at most daily. The list address is
72 fio@vger.kernel.org, subscribe by sending an email to
73 majordomo@vger.kernel.org with
77 in the body of the email. Archives can be found here:
79 http://www.spinics.net/lists/fio/
81 and archives for the old list can be found here:
83 http://maillist.kernel.dk/fio-devel/
89 Just type 'make' and 'make install'.
91 Note that GNU make is required. On BSD it's available from devel/gmake;
92 on Solaris it's in the SUNWgmake package. On platforms where GNU make
93 isn't the default, type 'gmake' instead of 'make'.
95 If your compile fails with an error like this:
98 In file included from fio.h:23,
100 os/os.h:15:20: error: libaio.h: No such file or directory
101 In file included from gettime.c:8:
102 fio.h:119: error: field 'iocb' has incomplete type
103 make: *** [gettime.o] Error 1
105 Check that you have the libaio development package installed. On RPM
106 based distros, it's typically called libaio-devel.
112 On Windows MinGW (http://www.mingw.org/) is required in order to
113 build fio. To create an MSI installer package install WiX 3.6 from
114 http://wix.sourceforge.net/releases/ and run dobuild.cmd from the
115 os/windows directory.
122 --debug Enable some debugging options (see below)
123 --output Write output to file
124 --runtime Runtime in seconds
125 --latency-log Generate per-job latency logs
126 --bandwidth-log Generate per-job bandwidth logs
127 --minimal Minimal (terse) output
128 --output-format=type Output format (terse,json,normal)
129 --terse-version=type Terse version output format (default 3, or 2 or 4).
130 --version Print version info and exit
131 --help Print this page
132 --cpuclock-test Perform test/validation of CPU clock
133 --cmdhelp=cmd Print command help, "all" for all of them
134 --enghelp=engine Print ioengine help, or list available ioengines
135 --enghelp=engine,cmd Print help for an ioengine cmd
136 --showcmd Turn a job file into command line options
137 --readonly Turn on safety read-only checks, preventing
139 --eta=when When ETA estimate should be printed
140 May be "always", "never" or "auto"
141 --section=name Only run specified section in job file.
142 Multiple sections can be specified.
143 --alloc-size=kb Set smalloc pool to this size in kb (def 1024)
144 --warnings-fatal Fio parser warnings are fatal
145 --max-jobs Maximum number of threads/processes to support
146 --server=args Start backend server. See Client/Server section.
147 --client=host Connect to specified backend.
150 Any parameters following the options will be assumed to be job files,
151 unless they match a job file parameter. You can add as many as you want,
152 each job file will be regarded as a separate group and fio will stonewall
155 The --readonly switch is an extra safety guard to prevent accidentally
156 turning on a write setting when that is not desired. Fio will only write
157 if rw=write/randwrite/rw/randrw is given, but this extra safety net can
158 be used as an extra precaution. It will also enable a write check in the
159 io engine core to prevent an accidental write due to a fio bug.
161 The debug switch allows adding options that trigger certain logging
162 options in fio. Currently the options are:
164 process Dump info related to processes
165 file Dump info related to file actions
166 io Dump info related to IO queuing
167 mem Dump info related to memory allocations
168 blktrace Dump info related to blktrace setup
169 verify Dump info related to IO verification
170 all Enable all debug options
171 random Dump info related to random offset generation
172 parse Dump info related to option matching and parsing
173 diskutil Dump info related to disk utilization updates
174 job:x Dump info only related to job number x
175 mutex Dump info only related to mutex up/down ops
176 profile Dump info related to profile extensions
177 time Dump info related to internal time keeping
178 ? or help Show available debug options.
180 You can specify as many as you want, eg --debug=file,mem will enable
181 file and memory debugging.
183 The section switch is meant to make it easier to ship a bigger job file
184 instead of several smaller ones. Say you define a job file with light,
185 moderate, and heavy parts. Then you can ask fio to run the given part
186 only by giving it a --section=heavy command line option. The section
187 option only applies to job sections, the reserved 'global' section is
188 always parsed and taken into account.
190 Fio has an internal allocator for shared memory called smalloc. It
191 allocates shared structures from this pool. The pool defaults to 1024k
192 in size, and can grow to 128 pools. If running large jobs with randommap
193 enabled it can run out of memory, in which case the --alloc-size switch
194 is handy for starting with a larger pool size. The backing store is
195 files in /tmp. Fio cleans up after itself, while it is running you
196 may see .fio_smalloc.* files in /tmp.
202 See the HOWTO file for a more detailed description of parameters and what
203 they mean. This file contains the terse version. You can describe big and
204 complex setups with the command line, but generally it's a lot easier to
205 just write a simple job file to describe the workload. The job file format
206 is in the ini style format, as that is easy to read and write for the user.
208 The job file parameters are:
210 name=x Use 'x' as the identifier for this job.
211 description=x 'x' is a text description of the job.
212 directory=x Use 'x' as the top level directory for storing files
213 filename=x Force the use of 'x' as the filename for all files
214 in this thread. If not given, fio will make up
215 a suitable filename based on the thread and file
217 rw=x 'x' may be: read, randread, write, randwrite,
218 rw (read-write mix), randrw (read-write random mix)
219 rwmixcycle=x Base cycle for switching between read and write
221 rwmixread=x 'x' percentage of rw mix ios will be reads. If
222 rwmixwrite is also given, the last of the two will
223 be used if they don't add up to 100%.
224 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
226 rand_repeatable=x The sequence of random io blocks can be repeatable
227 across runs, if 'x' is 1.
228 size=x Set file size to x bytes (x string can include k/m/g)
229 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
230 posixaio for POSIX aio, solarisaio for Solaris
231 native async IO, windowsaio for Windows native async IO,
232 sync for regular read/write io,
233 psync for regular pread/pwrite io, vsync for regular
234 readv/writev (with queuing emulation) mmap for mmap'ed
235 io, syslet-rw for syslet driven read/write, splice for
236 using splice/vmsplice, sg for direct SG_IO io, net
237 for network io, rdma for RDMA io, or cpuio for a
238 cycler burner load. sg only works on Linux on
239 SCSI (or SCSI-like devices, such as usb-storage or
240 sata/libata driven) devices. Fio also has a null
241 io engine, which is mainly used for testing
244 iodepth=x For async io, allow 'x' ios in flight
245 overwrite=x If 'x', layout a write file first.
246 nrfiles=x Spread io load over 'x' number of files per job,
248 prio=x Run io at prio X, 0-7 is the kernel allowed range
249 prioclass=x Run io at prio class X
250 bs=x Use 'x' for thread blocksize. May include k/m postfix.
251 bsrange=x-y Mix thread block sizes randomly between x and y. May
252 also include k/m postfix.
253 direct=x 1 for direct IO, 0 for buffered IO
254 thinktime=x "Think" x usec after each io
255 rate=x Throttle rate to x KB/sec
256 ratemin=x Quit if rate of x KB/sec can't be met
257 ratecycle=x ratemin averaged over x msecs
258 cpumask=x Only allow job to run on CPUs defined by mask.
259 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
260 numa_cpu_nodes=x,y-z Allow job to run on specified NUMA nodes' CPU.
261 numa_mem_policy=m:x,y-z Setup numa memory allocation policy.
262 'm' stands for policy, such as local, interleave,
263 bind, prefer, local. 'x, y-z' are numa node(s) for
264 memory allocation according to policy.
265 fsync=x If writing with buffered IO, fsync after every
266 'x' blocks have been written.
267 end_fsync=x If 'x', run fsync() after end-of-job.
268 startdelay=x Start this thread x seconds after startup
269 runtime=x Terminate x seconds after startup. Can include a
270 normal time suffix if not given in seconds, such as
271 'm' for minutes, 'h' for hours, and 'd' for days.
272 offset=x Start io at offset x (x string can include k/m/g)
273 invalidate=x Invalidate page cache for file prior to doing io
274 sync=x Use sync writes if x and writing buffered IO.
275 mem=x If x == malloc, use malloc for buffers. If x == shm,
276 use shared memory for buffers. If x == mmap, use
278 exitall When one thread quits, terminate the others
279 bwavgtime=x Average bandwidth stats over an x msec window.
280 create_serialize=x If 'x', serialize file creation.
281 create_fsync=x If 'x', run fsync() after file creation.
282 unlink If set, unlink files when done.
283 loops=x Run the job 'x' number of times.
284 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
285 use crc32 for verifies. md5 is 'safer', but crc32 is
286 a lot faster. Only makes sense for writing to a file.
287 For other types of checksumming, see HOWTO.
288 stonewall Wait for preceeding jobs to end before running.
289 numjobs=x Create 'x' similar entries for this job
290 thread Use pthreads instead of forked jobs
292 zoneskip=y Zone options must be paired. If given, the job
293 will skip y bytes for every x read/written. This
294 can be used to gauge hard drive speed over the entire
295 platter, without reading everything. Both x/y can
296 include k/m/g suffix.
297 read_iolog=x Open and read io pattern from file 'x'. The file format
298 is described in the HOWTO.
299 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
300 The iolog options are exclusive, if both given the
301 read iolog will be performed. Specify a separate file
302 for each job, otherwise the iologs will be interspersed
303 and the file may be corrupt.
304 write_bw_log Write a bandwidth log.
305 write_lat_log Write a latency log.
306 lockmem=x Lock down x amount of memory on the machine, to
307 simulate a machine with less memory available. x can
308 include k/m/g suffix.
309 nice=x Run job at given nice value.
310 exec_prerun=x Run 'x' before job io is begun.
311 exec_postrun=x Run 'x' after job io has finished.
312 ioscheduler=x Use ioscheduler 'x' for this job.
313 cpuload=x For a CPU io thread, percentage of CPU time to attempt
315 cpuchunks=x Split burn cycles into pieces of x usecs.
322 Normally you would run fio as a stand-alone application on the machine
323 where the IO workload should be generated. However, it is also possible to
324 run the frontend and backend of fio separately. This makes it possible to
325 have a fio server running on the machine(s) where the IO workload should
326 be running, while controlling it from another machine.
328 To start the server, you would do:
332 on that machine, where args defines what fio listens to. The arguments
333 are of the form 'type,hostname or IP,port'. 'type' is either 'ip' (or ip4)
334 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain socket.
335 'hostname' is either a hostname or IP address, and 'port' is the port to
336 listen to (only valid for TCP/IP, not a local socket). Some examples:
340 Start a fio server, listening on all interfaces on the default port (8765).
342 2) fio --server=ip:hostname,4444
344 Start a fio server, listening on IP belonging to hostname and on port 4444.
346 3) fio --server=ip6:::1,4444
348 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
350 4) fio --server=,4444
352 Start a fio server, listening on all interfaces on port 4444.
354 5) fio --server=1.2.3.4
356 Start a fio server, listening on IP 1.2.3.4 on the default port.
358 6) fio --server=sock:/tmp/fio.sock
360 Start a fio server, listening on the local socket /tmp/fio.sock.
362 When a server is running, you can connect to it from a client. The client
365 fio --local-args --client=server --remote-args <job file(s)>
367 where --local-args are arguments that are local to the client where it is
368 running, 'server' is the connect string, and --remote-args and <job file(s)>
369 are sent to the server. The 'server' string follows the same format as it
370 does on the server side, to allow IP/hostname/socket and port strings.
371 You can connect to multiple clients as well, to do that you could run:
373 fio --client=server2 <job file(s)> --client=server2 <job file(s)>
379 Fio works on (at least) Linux, Solaris, AIX, HP-UX, OSX, NetBSD, Windows
380 and FreeBSD. Some features and/or options may only be available on some of
381 the platforms, typically because those features only apply to that platform
382 (like the solarisaio engine, or the splice engine on Linux).
384 Some features are not available on FreeBSD/Solaris even if they could be
385 implemented, I'd be happy to take patches for that. An example of that is
386 disk utility statistics and (I think) huge page support, support for that
387 does exist in FreeBSD/Solaris.
389 Fio uses pthread mutexes for signalling and locking and FreeBSD does not
390 support process shared pthread mutexes. As a result, only threads are
391 supported on FreeBSD. This could be fixed with sysv ipc locking or
392 other locking alternatives.
394 Other *BSD platforms are untested, but fio should work there almost out
395 of the box. Since I don't do test runs or even compiles on those platforms,
396 your mileage may vary. Sending me patches for other platforms is greatly
397 appreciated. There's a lot of value in having the same test/benchmark tool
398 available on all platforms.
400 Note that POSIX aio is not enabled by default on AIX. If you get messages like:
402 Symbol resolution failed for /usr/lib/libc.a(posix_aio.o) because:
403 Symbol _posix_kaio_rdwr (number 2) is not exported from dependent module /unix.
405 you need to enable POSIX aio. Run the following commands as root:
407 # lsdev -C -l posix_aio0
408 posix_aio0 Defined Posix Asynchronous I/O
409 # cfgmgr -l posix_aio0
410 # lsdev -C -l posix_aio0
411 posix_aio0 Available Posix Asynchronous I/O
413 POSIX aio should work now. To make the change permanent:
415 # chdev -l posix_aio0 -P -a autoconfig='available'
422 Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
423 of the Linux IO subsystem and schedulers. He got tired of writing
424 specific test applications to simulate a given workload, and found that
425 the existing io benchmark/test tools out there weren't flexible enough
426 to do what he wanted.
428 Jens Axboe <axboe@kernel.dk> 20060905