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.
148 --idle-prof=option Report cpu idleness on a system or percpu basis
149 (option=system,percpu) or run unit work
150 calibration only (option=calibrate).
153 Any parameters following the options will be assumed to be job files,
154 unless they match a job file parameter. You can add as many as you want,
155 each job file will be regarded as a separate group and fio will stonewall
158 The --readonly switch is an extra safety guard to prevent accidentally
159 turning on a write setting when that is not desired. Fio will only write
160 if rw=write/randwrite/rw/randrw is given, but this extra safety net can
161 be used as an extra precaution. It will also enable a write check in the
162 io engine core to prevent an accidental write due to a fio bug.
164 The debug switch allows adding options that trigger certain logging
165 options in fio. Currently the options are:
167 process Dump info related to processes
168 file Dump info related to file actions
169 io Dump info related to IO queuing
170 mem Dump info related to memory allocations
171 blktrace Dump info related to blktrace setup
172 verify Dump info related to IO verification
173 all Enable all debug options
174 random Dump info related to random offset generation
175 parse Dump info related to option matching and parsing
176 diskutil Dump info related to disk utilization updates
177 job:x Dump info only related to job number x
178 mutex Dump info only related to mutex up/down ops
179 profile Dump info related to profile extensions
180 time Dump info related to internal time keeping
181 ? or help Show available debug options.
183 You can specify as many as you want, eg --debug=file,mem will enable
184 file and memory debugging.
186 The section switch is meant to make it easier to ship a bigger job file
187 instead of several smaller ones. Say you define a job file with light,
188 moderate, and heavy parts. Then you can ask fio to run the given part
189 only by giving it a --section=heavy command line option. The section
190 option only applies to job sections, the reserved 'global' section is
191 always parsed and taken into account.
193 Fio has an internal allocator for shared memory called smalloc. It
194 allocates shared structures from this pool. The pool defaults to 1024k
195 in size, and can grow to 128 pools. If running large jobs with randommap
196 enabled it can run out of memory, in which case the --alloc-size switch
197 is handy for starting with a larger pool size. The backing store is
198 files in /tmp. Fio cleans up after itself, while it is running you
199 may see .fio_smalloc.* files in /tmp.
205 See the HOWTO file for a more detailed description of parameters and what
206 they mean. This file contains the terse version. You can describe big and
207 complex setups with the command line, but generally it's a lot easier to
208 just write a simple job file to describe the workload. The job file format
209 is in the ini style format, as that is easy to read and write for the user.
211 The job file parameters are:
213 name=x Use 'x' as the identifier for this job.
214 description=x 'x' is a text description of the job.
215 directory=x Use 'x' as the top level directory for storing files
216 filename=x Force the use of 'x' as the filename for all files
217 in this thread. If not given, fio will make up
218 a suitable filename based on the thread and file
220 rw=x 'x' may be: read, randread, write, randwrite,
221 rw (read-write mix), randrw (read-write random mix)
222 rwmixcycle=x Base cycle for switching between read and write
224 rwmixread=x 'x' percentage of rw mix ios will be reads. If
225 rwmixwrite is also given, the last of the two will
226 be used if they don't add up to 100%.
227 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
229 rand_repeatable=x The sequence of random io blocks can be repeatable
230 across runs, if 'x' is 1.
231 size=x Set file size to x bytes (x string can include k/m/g)
232 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
233 posixaio for POSIX aio, solarisaio for Solaris
234 native async IO, windowsaio for Windows native async IO,
235 sync for regular read/write io,
236 psync for regular pread/pwrite io, vsync for regular
237 readv/writev (with queuing emulation) mmap for mmap'ed
238 io, syslet-rw for syslet driven read/write, splice for
239 using splice/vmsplice, sg for direct SG_IO io, net
240 for network io, rdma for RDMA io, or cpuio for a
241 cycler burner load. sg only works on Linux on
242 SCSI (or SCSI-like devices, such as usb-storage or
243 sata/libata driven) devices. Fio also has a null
244 io engine, which is mainly used for testing
247 iodepth=x For async io, allow 'x' ios in flight
248 overwrite=x If 'x', layout a write file first.
249 nrfiles=x Spread io load over 'x' number of files per job,
251 prio=x Run io at prio X, 0-7 is the kernel allowed range
252 prioclass=x Run io at prio class X
253 bs=x Use 'x' for thread blocksize. May include k/m postfix.
254 bsrange=x-y Mix thread block sizes randomly between x and y. May
255 also include k/m postfix.
256 direct=x 1 for direct IO, 0 for buffered IO
257 thinktime=x "Think" x usec after each io
258 rate=x Throttle rate to x KB/sec
259 ratemin=x Quit if rate of x KB/sec can't be met
260 ratecycle=x ratemin averaged over x msecs
261 cpumask=x Only allow job to run on CPUs defined by mask.
262 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
263 numa_cpu_nodes=x,y-z Allow job to run on specified NUMA nodes' CPU.
264 numa_mem_policy=m:x,y-z Setup numa memory allocation policy.
265 'm' stands for policy, such as local, interleave,
266 bind, prefer, local. 'x, y-z' are numa node(s) for
267 memory allocation according to policy.
268 fsync=x If writing with buffered IO, fsync after every
269 'x' blocks have been written.
270 end_fsync=x If 'x', run fsync() after end-of-job.
271 startdelay=x Start this thread x seconds after startup
272 runtime=x Terminate x seconds after startup. Can include a
273 normal time suffix if not given in seconds, such as
274 'm' for minutes, 'h' for hours, and 'd' for days.
275 offset=x Start io at offset x (x string can include k/m/g)
276 invalidate=x Invalidate page cache for file prior to doing io
277 sync=x Use sync writes if x and writing buffered IO.
278 mem=x If x == malloc, use malloc for buffers. If x == shm,
279 use shared memory for buffers. If x == mmap, use
281 exitall When one thread quits, terminate the others
282 bwavgtime=x Average bandwidth stats over an x msec window.
283 create_serialize=x If 'x', serialize file creation.
284 create_fsync=x If 'x', run fsync() after file creation.
285 unlink If set, unlink files when done.
286 loops=x Run the job 'x' number of times.
287 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
288 use crc32 for verifies. md5 is 'safer', but crc32 is
289 a lot faster. Only makes sense for writing to a file.
290 For other types of checksumming, see HOWTO.
291 stonewall Wait for preceeding jobs to end before running.
292 numjobs=x Create 'x' similar entries for this job
293 thread Use pthreads instead of forked jobs
295 zoneskip=y Zone options must be paired. If given, the job
296 will skip y bytes for every x read/written. This
297 can be used to gauge hard drive speed over the entire
298 platter, without reading everything. Both x/y can
299 include k/m/g suffix.
300 read_iolog=x Open and read io pattern from file 'x'. The file format
301 is described in the HOWTO.
302 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
303 The iolog options are exclusive, if both given the
304 read iolog will be performed. Specify a separate file
305 for each job, otherwise the iologs will be interspersed
306 and the file may be corrupt.
307 write_bw_log Write a bandwidth log.
308 write_lat_log Write a latency log.
309 lockmem=x Lock down x amount of memory on the machine, to
310 simulate a machine with less memory available. x can
311 include k/m/g suffix.
312 nice=x Run job at given nice value.
313 exec_prerun=x Run 'x' before job io is begun.
314 exec_postrun=x Run 'x' after job io has finished.
315 ioscheduler=x Use ioscheduler 'x' for this job.
316 cpuload=x For a CPU io thread, percentage of CPU time to attempt
318 cpuchunks=x Split burn cycles into pieces of x usecs.
325 Normally you would run fio as a stand-alone application on the machine
326 where the IO workload should be generated. However, it is also possible to
327 run the frontend and backend of fio separately. This makes it possible to
328 have a fio server running on the machine(s) where the IO workload should
329 be running, while controlling it from another machine.
331 To start the server, you would do:
335 on that machine, where args defines what fio listens to. The arguments
336 are of the form 'type,hostname or IP,port'. 'type' is either 'ip' (or ip4)
337 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain socket.
338 'hostname' is either a hostname or IP address, and 'port' is the port to
339 listen to (only valid for TCP/IP, not a local socket). Some examples:
343 Start a fio server, listening on all interfaces on the default port (8765).
345 2) fio --server=ip:hostname,4444
347 Start a fio server, listening on IP belonging to hostname and on port 4444.
349 3) fio --server=ip6:::1,4444
351 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
353 4) fio --server=,4444
355 Start a fio server, listening on all interfaces on port 4444.
357 5) fio --server=1.2.3.4
359 Start a fio server, listening on IP 1.2.3.4 on the default port.
361 6) fio --server=sock:/tmp/fio.sock
363 Start a fio server, listening on the local socket /tmp/fio.sock.
365 When a server is running, you can connect to it from a client. The client
368 fio --local-args --client=server --remote-args <job file(s)>
370 where --local-args are arguments that are local to the client where it is
371 running, 'server' is the connect string, and --remote-args and <job file(s)>
372 are sent to the server. The 'server' string follows the same format as it
373 does on the server side, to allow IP/hostname/socket and port strings.
374 You can connect to multiple clients as well, to do that you could run:
376 fio --client=server2 <job file(s)> --client=server2 <job file(s)>
382 Fio works on (at least) Linux, Solaris, AIX, HP-UX, OSX, NetBSD, Windows
383 and FreeBSD. Some features and/or options may only be available on some of
384 the platforms, typically because those features only apply to that platform
385 (like the solarisaio engine, or the splice engine on Linux).
387 Some features are not available on FreeBSD/Solaris even if they could be
388 implemented, I'd be happy to take patches for that. An example of that is
389 disk utility statistics and (I think) huge page support, support for that
390 does exist in FreeBSD/Solaris.
392 Fio uses pthread mutexes for signalling and locking and FreeBSD does not
393 support process shared pthread mutexes. As a result, only threads are
394 supported on FreeBSD. This could be fixed with sysv ipc locking or
395 other locking alternatives.
397 Other *BSD platforms are untested, but fio should work there almost out
398 of the box. Since I don't do test runs or even compiles on those platforms,
399 your mileage may vary. Sending me patches for other platforms is greatly
400 appreciated. There's a lot of value in having the same test/benchmark tool
401 available on all platforms.
403 Note that POSIX aio is not enabled by default on AIX. If you get messages like:
405 Symbol resolution failed for /usr/lib/libc.a(posix_aio.o) because:
406 Symbol _posix_kaio_rdwr (number 2) is not exported from dependent module /unix.
408 you need to enable POSIX aio. Run the following commands as root:
410 # lsdev -C -l posix_aio0
411 posix_aio0 Defined Posix Asynchronous I/O
412 # cfgmgr -l posix_aio0
413 # lsdev -C -l posix_aio0
414 posix_aio0 Available Posix Asynchronous I/O
416 POSIX aio should work now. To make the change permanent:
418 # chdev -l posix_aio0 -P -a autoconfig='available'
425 Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
426 of the Linux IO subsystem and schedulers. He got tired of writing
427 specific test applications to simulate a given workload, and found that
428 the existing io benchmark/test tools out there weren't flexible enough
429 to do what he wanted.
431 Jens Axboe <axboe@kernel.dk> 20060905