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 The http protocol also works, path is the same.
21 Snapshots are frequently generated and they include the git meta data as
22 well. You can download them here:
24 http://brick.kernel.dk/snaps/
26 Pascal Bleser <guru@unixtech.be> has fio RPMs in his repository for
27 SUSE variants, you can find them here:
29 http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio
31 Dag Wieƫrs has RPMs for Red Hat related distros, find them here:
33 http://dag.wieers.com/rpm/packages/fio/
35 Mandriva has integrated fio into their package repository, so installing
36 on that distro should be as easy as typing 'urpmi fio'.
42 There's a mailing list associated with fio. It's meant for general
43 discussion, bug reporting, questions - basically anything that has to
44 do with fio. An automated mail detailing recent commits is automatically
45 sent to the list at most daily. The list address is fio-devel@kernel.dk,
46 subscribe by sending an empty email to fio-devel+subscribe@kernel.dk.
52 Just type 'make' and 'make install'. If on FreeBSD, for now you have to
53 specify the FreeBSD Makefile with -f, eg:
55 $ make -f Makefile.Freebsd && make -f Makefile.FreeBSD install
57 Likewise with OpenSolaris, use the Makefile.solaris to compile there.
58 This might change in the future if I opt for an autoconf type setup.
65 --debug Enable some debugging options (see below)
66 --output Write output to file
67 --runtime Runtime in seconds
68 --latency-log Generate per-job latency logs
69 --bandwidth-log Generate per-job bandwidth logs
70 --minimal Minimal (terse) output
71 --version Print version info and exit
72 --help Print this page
73 --cmdhelp=cmd Print command help, "all" for all of them
74 --showcmd Turn a job file into command line options
75 --readonly Turn on safety read-only checks
76 --eta=when When ETA estimate should be printed
77 May be "always", "never" or "auto"
80 Any parameters following the options will be assumed to be job files,
81 unless they match a job file parameter. You can add as many as you want,
82 each job file will be regarded as a separate group and fio will stonewall
85 The --readonly switch is an extra safety guard to prevent accidentically
86 turning on a write setting when that is not desired. Fio will only write
87 if rw=write/randwrite/rw/randrw is given, but this extra safety net can
88 be used as an extra precaution. It will also enable a write check in the
89 io engine core to prevent an accidental write due to a fio bug.
91 The debug switch allows adding options that trigger certain logging
92 options in fio. Currently the options are:
94 process Dump info related to processes
95 file Dump info related to file actions
96 io Dump info related to IO queuing
97 mem Dump info related to memory allocations
98 blktrace Dump info related to blktrace setup
99 verify Dump info related to IO verification
100 all Enable all debug options
101 ? or help Show available debug options.
103 You can specify as many as you want, eg --debug=file,mem will enable
104 file and memory debugging.
110 See the HOWTO file for a more detailed description of parameters and what
111 they mean. This file contains the terse version. You can describe big and
112 complex setups with the command line, but generally it's a lot easier to
113 just write a simple job file to describe the workload. The job file format
114 is in the ini style format, as that is easy to read and write for the user.
116 The job file parameters are:
118 name=x Use 'x' as the identifier for this job.
119 description=x 'x' is a text description of the job.
120 directory=x Use 'x' as the top level directory for storing files
121 filename=x Force the use of 'x' as the filename for all files
122 in this thread. If not given, fio will make up
123 a suitable filename based on the thread and file
125 rw=x 'x' may be: read, randread, write, randwrite,
126 rw (read-write mix), randrw (read-write random mix)
127 rwmixcycle=x Base cycle for switching between read and write
129 rwmixread=x 'x' percentage of rw mix ios will be reads. If
130 rwmixwrite is also given, the last of the two will
131 be used if they don't add up to 100%.
132 rwmixwrite=x 'x' percentage of rw mix ios will be writes. See
134 rand_repeatable=x The sequence of random io blocks can be repeatable
135 across runs, if 'x' is 1.
136 size=x Set file size to x bytes (x string can include k/m/g)
137 ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio,
138 posixaio for POSIX aio, sync for regular read/write io,
139 psync for regular pread/pwrite io, mmap for mmap'ed io,
140 syslet-rw for syslet driven read/write, splice for using
141 splice/vmsplice, sgio for direct SG_IO io, net for
142 network io, or cpuio for a cycler burner load. sgio only
143 works on Linux on SCSI (or SCSI-like devices, such as
144 usb-storage or sata/libata driven) devices. Fio also has
145 a null io engine, which is mainly used for testing fio
147 iodepth=x For async io, allow 'x' ios in flight
148 overwrite=x If 'x', layout a write file first.
149 nrfiles=x Spread io load over 'x' number of files per job,
151 prio=x Run io at prio X, 0-7 is the kernel allowed range
152 prioclass=x Run io at prio class X
153 bs=x Use 'x' for thread blocksize. May include k/m postfix.
154 bsrange=x-y Mix thread block sizes randomly between x and y. May
155 also include k/m postfix.
156 direct=x 1 for direct IO, 0 for buffered IO
157 thinktime=x "Think" x usec after each io
158 rate=x Throttle rate to x KiB/sec
159 ratemin=x Quit if rate of x KiB/sec can't be met
160 ratecycle=x ratemin averaged over x msecs
161 cpumask=x Only allow job to run on CPUs defined by mask.
162 cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
163 fsync=x If writing with buffered IO, fsync after every
164 'x' blocks have been written.
165 end_fsync=x If 'x', run fsync() after end-of-job.
166 startdelay=x Start this thread x seconds after startup
167 runtime=x Terminate x seconds after startup. Can include a
168 normal time suffix if not given in seconds, such as
169 'm' for minutes, 'h' for hours, and 'd' for days.
170 offset=x Start io at offset x (x string can include k/m/g)
171 invalidate=x Invalidate page cache for file prior to doing io
172 sync=x Use sync writes if x and writing buffered IO.
173 mem=x If x == malloc, use malloc for buffers. If x == shm,
174 use shared memory for buffers. If x == mmap, use
176 exitall When one thread quits, terminate the others
177 bwavgtime=x Average bandwidth stats over an x msec window.
178 create_serialize=x If 'x', serialize file creation.
179 create_fsync=x If 'x', run fsync() after file creation.
180 unlink If set, unlink files when done.
181 loops=x Run the job 'x' number of times.
182 verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32,
183 use crc32 for verifies. md5 is 'safer', but crc32 is
184 a lot faster. Only makes sense for writing to a file.
185 stonewall Wait for preceeding jobs to end before running.
186 numjobs=x Create 'x' similar entries for this job
187 thread Use pthreads instead of forked jobs
189 zoneskip=y Zone options must be paired. If given, the job
190 will skip y bytes for every x read/written. This
191 can be used to gauge hard drive speed over the entire
192 platter, without reading everything. Both x/y can
193 include k/m/g suffix.
194 iolog=x Open and read io pattern from file 'x'. The file must
195 contain one io action per line in the following format:
197 where with rw=0/1 for read/write, and the offset
198 and length entries being in bytes.
199 write_iolog=x Write an iolog to file 'x' in the same format as iolog.
200 The iolog options are exclusive, if both given the
201 read iolog will be performed.
202 write_bw_log Write a bandwidth log.
203 write_lat_log Write a latency log.
204 lockmem=x Lock down x amount of memory on the machine, to
205 simulate a machine with less memory available. x can
206 include k/m/g suffix.
207 nice=x Run job at given nice value.
208 exec_prerun=x Run 'x' before job io is begun.
209 exec_postrun=x Run 'x' after job io has finished.
210 ioscheduler=x Use ioscheduler 'x' for this job.
211 cpuload=x For a CPU io thread, percentage of CPU time to attempt
213 cpuchunks=x Split burn cycles into pieces of x usecs.
219 Fio was written by Jens Axboe <axboe@kernel.dk> to enable flexible testing
220 of the Linux IO subsystem and schedulers. He got tired of writing
221 specific test applications to simulate a given workload, and found that
222 the existing io benchmark/test tools out there weren't flexible enough
223 to do what he wanted.
225 Jens Axboe <axboe@kernel.dk> 20060905