1 .TH fio 1 "October 2013" "User Manual"
3 fio \- flexible I/O tester
6 [\fIoptions\fR] [\fIjobfile\fR]...
9 is a tool that will spawn a number of threads or processes doing a
10 particular type of I/O action as specified by the user.
11 The typical use of fio is to write a job file matching the I/O load
12 one wants to simulate.
15 .BI \-\-debug \fR=\fPtype
16 Enable verbose tracing of various fio actions. May be `all' for all types
17 or individual types separated by a comma (eg \-\-debug=io,file). `help' will
18 list all available tracing options.
20 .BI \-\-output \fR=\fPfilename
21 Write output to \fIfilename\fR.
23 .BI \-\-runtime \fR=\fPruntime
24 Limit run time to \fIruntime\fR seconds.
27 Generate per-job latency logs.
30 Generate per-job bandwidth logs.
33 Print statistics in a terse, semicolon-delimited format.
36 Display version information and exit.
38 .BI \-\-terse\-version \fR=\fPversion
39 Set terse version output format (Current version 3, or older version 2).
42 Display usage information and exit.
44 .BI \-\-cmdhelp \fR=\fPcommand
45 Print help information for \fIcommand\fR. May be `all' for all commands.
47 .BI \-\-enghelp \fR=\fPioengine[,command]
48 List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR defined by \fIioengine\fR.
50 .BI \-\-showcmd \fR=\fPjobfile
51 Convert \fIjobfile\fR to a set of command-line options.
53 .BI \-\-eta \fR=\fPwhen
54 Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
55 be one of `always', `never' or `auto'.
57 .BI \-\-eta\-newline \fR=\fPtime
58 Force an ETA newline for every `time` period passed.
60 .BI \-\-status\-interval \fR=\fPtime
61 Report full output status every `time` period passed.
64 Turn on safety read-only checks, preventing any attempted write.
66 .BI \-\-section \fR=\fPsec
67 Only run section \fIsec\fR from job file. Multiple of these options can be given, adding more sections to run.
69 .BI \-\-alloc\-size \fR=\fPkb
70 Set the internal smalloc pool size to \fIkb\fP kilobytes.
72 .BI \-\-warnings\-fatal
73 All fio parser warnings are fatal, causing fio to exit with an error.
75 .BI \-\-max\-jobs \fR=\fPnr
76 Set the maximum allowed number of jobs (threads/processes) to support.
78 .BI \-\-server \fR=\fPargs
79 Start a backend server, with \fIargs\fP specifying what to listen to. See client/server section.
81 .BI \-\-daemonize \fR=\fPpidfile
82 Background a fio server, writing the pid to the given pid file.
84 .BI \-\-client \fR=\fPhost
85 Instead of running the jobs locally, send and run them on the given host.
87 .BI \-\-idle\-prof \fR=\fPoption
88 Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate).
90 Job files are in `ini' format. They consist of one or more
91 job definitions, which begin with a job name in square brackets and
92 extend to the next job name. The job name can be any ASCII string
93 except `global', which has a special meaning. Following the job name is
94 a sequence of zero or more parameters, one per line, that define the
95 behavior of the job. Any line starting with a `;' or `#' character is
96 considered a comment and ignored.
98 If \fIjobfile\fR is specified as `-', the job file will be read from
101 The global section contains default parameters for jobs specified in the
102 job file. A job is only affected by global sections residing above it,
103 and there may be any number of global sections. Specific job definitions
104 may override any parameter set in global sections.
107 Some parameters may take arguments of a specific type. The types used are:
110 String: a sequence of alphanumeric characters.
113 SI integer: a whole number, possibly containing a suffix denoting the base unit
114 of the value. Accepted suffixes are `k', 'M', 'G', 'T', and 'P', denoting
115 kilo (1024), mega (1024^2), giga (1024^3), tera (1024^4), and peta (1024^5)
116 respectively. The suffix is not case sensitive. If prefixed with '0x', the
117 value is assumed to be base 16 (hexadecimal). A suffix may include a trailing 'b',
118 for instance 'kb' is identical to 'k'. You can specify a base 10 value
119 by using 'KiB', 'MiB', 'GiB', etc. This is useful for disk drives where
120 values are often given in base 10 values. Specifying '30GiB' will get you
124 Boolean: a true or false value. `0' denotes false, `1' denotes true.
127 Integer range: a range of integers specified in the format
128 \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and
129 \fIupper\fR may contain a suffix as described above. If an option allows two
130 sets of ranges, they are separated with a `,' or `/' character. For example:
134 List of floating numbers: A list of floating numbers, separated by
139 May be used to override the job name. On the command line, this parameter
140 has the special purpose of signalling the start of a new job.
142 .BI description \fR=\fPstr
143 Human-readable description of the job. It is printed when the job is run, but
144 otherwise has no special purpose.
146 .BI directory \fR=\fPstr
147 Prefix filenames with this directory. Used to place files in a location other
150 .BI filename \fR=\fPstr
152 normally makes up a file name based on the job name, thread number, and file
153 number. If you want to share files between threads in a job or several jobs,
154 specify a \fIfilename\fR for each of them to override the default.
155 If the I/O engine is file-based, you can specify
156 a number of files by separating the names with a `:' character. `\-' is a
157 reserved name, meaning stdin or stdout, depending on the read/write direction
160 .BI filename_format \fR=\fPstr
161 If sharing multiple files between jobs, it is usually necessary to have
162 fio generate the exact names that you want. By default, fio will name a file
163 based on the default file format specification of
164 \fBjobname.jobnumber.filenumber\fP. With this option, that can be
165 customized. Fio will recognize and replace the following keywords in this
171 The name of the worker thread or process.
174 The incremental number of the worker thread or process.
177 The incremental number of the file for that worker thread or process.
180 To have dependent jobs share a set of files, this option can be set to
181 have fio generate filenames that are shared between the two. For instance,
182 if \fBtestfiles.$filenum\fR is specified, file number 4 for any job will
183 be named \fBtestfiles.4\fR. The default of \fB$jobname.$jobnum.$filenum\fR
184 will be used if no other format specifier is given.
188 .BI lockfile \fR=\fPstr
189 Fio defaults to not locking any files before it does IO to them. If a file or
190 file descriptor is shared, fio can serialize IO to that file to make the end
191 result consistent. This is usual for emulating real workloads that share files.
197 No locking. This is the default.
200 Only one thread or process may do IO at the time, excluding all others.
203 Read-write locking on the file. Many readers may access the file at the same
204 time, but writes get exclusive access.
208 .BI opendir \fR=\fPstr
209 Recursively open any files below directory \fIstr\fR.
211 .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr
212 Type of I/O pattern. Accepted values are:
223 Sequential trim (Linux block devices only).
232 Random trim (Linux block devices only).
235 Mixed sequential reads and writes.
238 Mixed random reads and writes.
241 For mixed I/O, the default split is 50/50. For certain types of io the result
242 may still be skewed a bit, since the speed may be different. It is possible to
243 specify a number of IO's to do before getting a new offset, this is done by
244 appending a `:\fI<nr>\fR to the end of the string given. For a random read, it
245 would look like \fBrw=randread:8\fR for passing in an offset modifier with a
246 value of 8. If the postfix is used with a sequential IO pattern, then the value
247 specified will be added to the generated offset for each IO. For instance,
248 using \fBrw=write:4k\fR will skip 4k for every write. It turns sequential IO
249 into sequential IO with holes. See the \fBrw_sequencer\fR option.
252 .BI rw_sequencer \fR=\fPstr
253 If an offset modifier is given by appending a number to the \fBrw=<str>\fR line,
254 then this option controls how that number modifies the IO offset being
255 generated. Accepted values are:
260 Generate sequential offset
263 Generate the same offset
266 \fBsequential\fR is only useful for random IO, where fio would normally
267 generate a new random offset for every IO. If you append eg 8 to randread, you
268 would get a new random offset for every 8 IO's. The result would be a seek for
269 only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify
270 that. As sequential IO is already sequential, setting \fBsequential\fR for that
271 would not result in any differences. \fBidentical\fR behaves in a similar
272 fashion, except it sends the same offset 8 number of times before generating a
277 .BI kb_base \fR=\fPint
278 The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage
279 manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious
280 reasons. Allowed values are 1024 or 1000, with 1024 being the default.
282 .BI unified_rw_reporting \fR=\fPbool
283 Fio normally reports statistics on a per data direction basis, meaning that
284 read, write, and trim are accounted and reported separately. If this option is
285 set, the fio will sum the results and report them as "mixed" instead.
287 .BI randrepeat \fR=\fPbool
288 Seed the random number generator in a predictable way so results are repeatable
289 across runs. Default: true.
291 .BI use_os_rand \fR=\fPbool
292 Fio can either use the random generator supplied by the OS to generator random
293 offsets, or it can use it's own internal generator (based on Tausworthe).
294 Default is to use the internal generator, which is often of better quality and
295 faster. Default: false.
297 .BI fallocate \fR=\fPstr
298 Whether pre-allocation is performed when laying down files. Accepted values
304 Do not pre-allocate space.
307 Pre-allocate via \fBposix_fallocate\fR\|(3).
310 Pre-allocate via \fBfallocate\fR\|(2) with FALLOC_FL_KEEP_SIZE set.
313 Backward-compatible alias for 'none'.
316 Backward-compatible alias for 'posix'.
319 May not be available on all supported platforms. 'keep' is only
320 available on Linux. If using ZFS on Solaris this must be set to 'none'
321 because ZFS doesn't support it. Default: 'posix'.
324 .BI fadvise_hint \fR=\fPbool
325 Use of \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
326 are likely to be issued. Default: true.
329 Total size of I/O for this job. \fBfio\fR will run until this many bytes have
330 been transferred, unless limited by other options (\fBruntime\fR, for instance).
331 Unless \fBnrfiles\fR and \fBfilesize\fR options are given, this amount will be
332 divided between the available files for the job. If not set, fio will use the
333 full size of the given files or devices. If the files do not exist, size
334 must be given. It is also possible to give size as a percentage between 1 and
335 100. If size=20% is given, fio will use 20% of the full size of the given files
338 .BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool
339 Sets size to something really large and waits for ENOSPC (no space left on
340 device) as the terminating condition. Only makes sense with sequential write.
341 For a read workload, the mount point will be filled first then IO started on
342 the result. This option doesn't make sense if operating on a raw device node,
343 since the size of that is already known by the file system. Additionally,
344 writing beyond end-of-device will not return ENOSPC there.
346 .BI filesize \fR=\fPirange
347 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
348 for files at random within the given range, limited to \fBsize\fR in total (if
349 that is given). If \fBfilesize\fR is not specified, each created file is the
352 .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
353 Block size for I/O units. Default: 4k. Values for reads, writes, and trims
354 can be specified separately in the format \fIread\fR,\fIwrite\fR,\fItrim\fR
355 either of which may be empty to leave that value at its default. If a trailing
356 comma isn't given, the remainder will inherit the last value set.
358 .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
359 Specify a range of I/O block sizes. The issued I/O unit will always be a
360 multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
361 to both reads and writes if only one range is given, but can be specified
362 separately with a comma separating the values. Example: bsrange=1k-4k,2k-8k.
363 Also (see \fBblocksize\fR).
365 .BI bssplit \fR=\fPstr
366 This option allows even finer grained control of the block sizes issued,
367 not just even splits between them. With this option, you can weight various
368 block sizes for exact control of the issued IO for a job that has mixed
369 block sizes. The format of the option is bssplit=blocksize/percentage,
370 optionally adding as many definitions as needed separated by a colon.
371 Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
372 blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
373 splits to reads and writes. The format is identical to what the
374 \fBbs\fR option accepts, the read and write parts are separated with a
377 .B blocksize_unaligned\fR,\fP bs_unaligned
378 If set, any size in \fBblocksize_range\fR may be used. This typically won't
379 work with direct I/O, as that normally requires sector alignment.
381 .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
382 At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
383 the minimum blocksize given. Minimum alignment is typically 512b
384 for using direct IO, though it usually depends on the hardware block size.
385 This option is mutually exclusive with using a random map for files, so it
386 will turn off that option.
388 .BI bs_is_seq_rand \fR=\fPbool
389 If this option is set, fio will use the normal read,write blocksize settings as
390 sequential,random instead. Any random read or write will use the WRITE
391 blocksize settings, and any sequential read or write will use the READ
395 Initialise buffers with all zeros. Default: fill buffers with random data.
398 If this option is given, fio will refill the IO buffers on every submit. The
399 default is to only fill it at init time and reuse that data. Only makes sense
400 if zero_buffers isn't specified, naturally. If data verification is enabled,
401 refill_buffers is also automatically enabled.
403 .BI scramble_buffers \fR=\fPbool
404 If \fBrefill_buffers\fR is too costly and the target is using data
405 deduplication, then setting this option will slightly modify the IO buffer
406 contents to defeat normal de-dupe attempts. This is not enough to defeat
407 more clever block compression attempts, but it will stop naive dedupe
408 of blocks. Default: true.
410 .BI buffer_compress_percentage \fR=\fPint
411 If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
412 that compress to the specified level. Fio does this by providing a mix of
413 random data and zeroes. Note that this is per block size unit, for file/disk
414 wide compression level that matches this setting, you'll also want to set
415 \fBrefill_buffers\fR.
417 .BI buffer_compress_chunk \fR=\fPint
418 See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how
419 big the ranges of random data and zeroed data is. Without this set, fio will
420 provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by
421 the remaining zeroed. With this set to some chunk size smaller than the block
422 size, fio can alternate random and zeroed data throughout the IO buffer.
424 .BI nrfiles \fR=\fPint
425 Number of files to use for this job. Default: 1.
427 .BI openfiles \fR=\fPint
428 Number of files to keep open at the same time. Default: \fBnrfiles\fR.
430 .BI file_service_type \fR=\fPstr
431 Defines how files to service are selected. The following types are defined:
436 Choose a file at random.
439 Round robin over open files (default).
442 Do each file in the set sequentially.
445 The number of I/Os to issue before switching a new file can be specified by
446 appending `:\fIint\fR' to the service type.
449 .BI ioengine \fR=\fPstr
450 Defines how the job issues I/O. The following types are defined:
455 Basic \fBread\fR\|(2) or \fBwrite\fR\|(2) I/O. \fBfseek\fR\|(2) is used to
456 position the I/O location.
459 Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.
462 Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by
463 coalescing adjacent IOs into a single submission.
466 Basic \fBpreadv\fR\|(2) or \fBpwritev\fR\|(2) I/O.
469 Linux native asynchronous I/O. This ioengine defines engine specific options.
472 POSIX asynchronous I/O using \fBaio_read\fR\|(3) and \fBaio_write\fR\|(3).
475 Solaris native asynchronous I/O.
478 Windows native asynchronous I/O.
481 File is memory mapped with \fBmmap\fR\|(2) and data copied using
485 \fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
486 transfer data from user-space to the kernel.
489 Use the syslet system calls to make regular read/write asynchronous.
492 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
493 the target is an sg character device, we use \fBread\fR\|(2) and
494 \fBwrite\fR\|(2) for asynchronous I/O.
497 Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
498 itself and for debugging and testing purposes.
501 Transfer over the network. The protocol to be used can be defined with the
502 \fBprotocol\fR parameter. Depending on the protocol, \fBfilename\fR,
503 \fBhostname\fR, \fBport\fR, or \fBlisten\fR must be specified.
504 This ioengine defines engine specific options.
507 Like \fBnet\fR, but uses \fBsplice\fR\|(2) and \fBvmsplice\fR\|(2) to map data
508 and send/receive. This ioengine defines engine specific options.
511 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
512 \fBcpucycles\fR parameters.
515 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
516 approach to asynchronous I/O.
518 See <http://www.xmailserver.org/guasi\-lib.html>.
521 The RDMA I/O engine supports both RDMA memory semantics (RDMA_WRITE/RDMA_READ)
522 and channel semantics (Send/Recv) for the InfiniBand, RoCE and iWARP protocols.
525 Loads an external I/O engine object file. Append the engine filename as
529 IO engine that does regular linux native fallocate call to simulate data
530 transfer as fio ioengine
532 DDIR_READ does fallocate(,mode = FALLOC_FL_KEEP_SIZE,)
534 DIR_WRITE does fallocate(,mode = 0)
536 DDIR_TRIM does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE)
539 IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity
540 request to DDIR_WRITE event
545 .BI iodepth \fR=\fPint
546 Number of I/O units to keep in flight against the file. Note that increasing
547 iodepth beyond 1 will not affect synchronous ioengines (except for small
548 degress when verify_async is in use). Even async engines my impose OS
549 restrictions causing the desired depth not to be achieved. This may happen on
550 Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is
551 not async on that OS. Keep an eye on the IO depth distribution in the
552 fio output to verify that the achieved depth is as expected. Default: 1.
554 .BI iodepth_batch \fR=\fPint
555 Number of I/Os to submit at once. Default: \fBiodepth\fR.
557 .BI iodepth_batch_complete \fR=\fPint
558 This defines how many pieces of IO to retrieve at once. It defaults to 1 which
559 means that we'll ask for a minimum of 1 IO in the retrieval process from the
560 kernel. The IO retrieval will go on until we hit the limit set by
561 \fBiodepth_low\fR. If this variable is set to 0, then fio will always check for
562 completed events before queuing more IO. This helps reduce IO latency, at the
563 cost of more retrieval system calls.
565 .BI iodepth_low \fR=\fPint
566 Low watermark indicating when to start filling the queue again. Default:
569 .BI direct \fR=\fPbool
570 If true, use non-buffered I/O (usually O_DIRECT). Default: false.
572 .BI atomic \fR=\fPbool
573 If value is true, attempt to use atomic direct IO. Atomic writes are guaranteed
574 to be stable once acknowledged by the operating system. Only Linux supports
577 .BI buffered \fR=\fPbool
578 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
581 .BI offset \fR=\fPint
582 Offset in the file to start I/O. Data before the offset will not be touched.
584 .BI offset_increment \fR=\fPint
585 If this is provided, then the real offset becomes the
586 offset + offset_increment * thread_number, where the thread number is a counter
587 that starts at 0 and is incremented for each job. This option is useful if
588 there are several jobs which are intended to operate on a file in parallel in
589 disjoint segments, with even spacing between the starting points.
591 .BI number_ios \fR=\fPint
592 Fio will normally perform IOs until it has exhausted the size of the region
593 set by \fBsize\fR, or if it exhaust the allocated time (or hits an error
594 condition). With this setting, the range/size can be set independently of
595 the number of IOs to perform. When fio reaches this number, it will exit
596 normally and report status.
599 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
600 0, don't sync. Default: 0.
602 .BI fdatasync \fR=\fPint
603 Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the
604 data parts of the file. Default: 0.
606 .BI write_barrier \fR=\fPint
607 Make every Nth write a barrier write.
609 .BI sync_file_range \fR=\fPstr:int
610 Use \fBsync_file_range\fR\|(2) for every \fRval\fP number of write operations. Fio will
611 track range of writes that have happened since the last \fBsync_file_range\fR\|(2) call.
612 \fRstr\fP can currently be one or more of:
616 SYNC_FILE_RANGE_WAIT_BEFORE
619 SYNC_FILE_RANGE_WRITE
622 SYNC_FILE_RANGE_WRITE
626 So if you do sync_file_range=wait_before,write:8, fio would use
627 \fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes.
628 Also see the \fBsync_file_range\fR\|(2) man page. This option is Linux specific.
630 .BI overwrite \fR=\fPbool
631 If writing, setup the file first and do overwrites. Default: false.
633 .BI end_fsync \fR=\fPbool
634 Sync file contents when a write stage has completed. Default: false.
636 .BI fsync_on_close \fR=\fPbool
637 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
638 it will happen on every close, not just at the end of the job. Default: false.
640 .BI rwmixread \fR=\fPint
641 Percentage of a mixed workload that should be reads. Default: 50.
643 .BI rwmixwrite \fR=\fPint
644 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
645 \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two
646 overrides the first. This may interfere with a given rate setting, if fio is
647 asked to limit reads or writes to a certain rate. If that is the case, then
648 the distribution may be skewed. Default: 50.
650 .BI random_distribution \fR=\fPstr:float
651 By default, fio will use a completely uniform random distribution when asked
652 to perform random IO. Sometimes it is useful to skew the distribution in
653 specific ways, ensuring that some parts of the data is more hot than others.
654 Fio includes the following distribution models:
658 Uniform random distribution
668 When using a zipf or pareto distribution, an input value is also needed to
669 define the access pattern. For zipf, this is the zipf theta. For pareto,
670 it's the pareto power. Fio includes a test program, genzipf, that can be
671 used visualize what the given input values will yield in terms of hit rates.
672 If you wanted to use zipf with a theta of 1.2, you would use
673 random_distribution=zipf:1.2 as the option. If a non-uniform model is used,
674 fio will disable use of the random map.
676 .BI percentage_random \fR=\fPint
677 For a random workload, set how big a percentage should be random. This defaults
678 to 100%, in which case the workload is fully random. It can be set from
679 anywhere from 0 to 100. Setting it to 0 would make the workload fully
680 sequential. It is possible to set different values for reads, writes, and
681 trim. To do so, simply use a comma separated list. See \fBblocksize\fR.
684 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
685 this parameter is given, a new offset will be chosen without looking at past
686 I/O history. This parameter is mutually exclusive with \fBverify\fR.
688 .BI softrandommap \fR=\fPbool
689 See \fBnorandommap\fR. If fio runs with the random block map enabled and it
690 fails to allocate the map, if this option is set it will continue without a
691 random block map. As coverage will not be as complete as with random maps, this
692 option is disabled by default.
694 .BI random_generator \fR=\fPstr
695 Fio supports the following engines for generating IO offsets for random IO:
699 Strong 2^88 cycle random number generator
702 Linear feedback shift register generator
706 Tausworthe is a strong random number generator, but it requires tracking on the
707 side if we want to ensure that blocks are only read or written once. LFSR
708 guarantees that we never generate the same offset twice, and it's also less
709 computationally expensive. It's not a true random generator, however, though
710 for IO purposes it's typically good enough. LFSR only works with single block
711 sizes, not with workloads that use multiple block sizes. If used with such a
712 workload, fio may read or write some blocks multiple times.
715 Run job with given nice value. See \fBnice\fR\|(2).
718 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
721 .BI prioclass \fR=\fPint
722 Set I/O priority class. See \fBionice\fR\|(1).
724 .BI thinktime \fR=\fPint
725 Stall job for given number of microseconds between issuing I/Os.
727 .BI thinktime_spin \fR=\fPint
728 Pretend to spend CPU time for given number of microseconds, sleeping the rest
729 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
731 .BI thinktime_blocks \fR=\fPint
732 Only valid if thinktime is set - control how many blocks to issue, before
733 waiting \fBthinktime\fR microseconds. If not set, defaults to 1 which will
734 make fio wait \fBthinktime\fR microseconds after every block. This
735 effectively makes any queue depth setting redundant, since no more than 1 IO
736 will be queued before we have to complete it and do our thinktime. In other
737 words, this setting effectively caps the queue depth if the latter is larger.
741 Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix
742 rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each,
743 or you can specify read and writes separately. Using \fBrate\fR=1m,500k would
744 limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes
745 can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only
746 limit writes (to 500KB/sec), the latter will only limit reads.
748 .BI ratemin \fR=\fPint
749 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
750 Failing to meet this requirement will cause the job to exit. The same format
751 as \fBrate\fR is used for read vs write separation.
753 .BI rate_iops \fR=\fPint
754 Cap the bandwidth to this number of IOPS. Basically the same as rate, just
755 specified independently of bandwidth. The same format as \fBrate\fR is used for
756 read vs write separation. If \fBblocksize\fR is a range, the smallest block
757 size is used as the metric.
759 .BI rate_iops_min \fR=\fPint
760 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
761 is used for read vs write separation.
763 .BI ratecycle \fR=\fPint
764 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
765 milliseconds. Default: 1000ms.
767 .BI latency_target \fR=\fPint
768 If set, fio will attempt to find the max performance point that the given
769 workload will run at while maintaining a latency below this target. The
770 values is given in microseconds. See \fBlatency_window\fR and
771 \fBlatency_percentile\fR.
773 .BI latency_window \fR=\fPint
774 Used with \fBlatency_target\fR to specify the sample window that the job
775 is run at varying queue depths to test the performance. The value is given
778 .BI latency_percentile \fR=\fPfloat
779 The percentage of IOs that must fall within the criteria specified by
780 \fBlatency_target\fR and \fBlatency_window\fR. If not set, this defaults
781 to 100.0, meaning that all IOs must be equal or below to the value set
782 by \fBlatency_target\fR.
784 .BI max_latency \fR=\fPint
785 If set, fio will exit the job if it exceeds this maximum latency. It will exit
788 .BI cpumask \fR=\fPint
789 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
790 may run on. See \fBsched_setaffinity\fR\|(2).
792 .BI cpus_allowed \fR=\fPstr
793 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
795 .BI numa_cpu_nodes \fR=\fPstr
796 Set this job running on specified NUMA nodes' CPUs. The arguments allow
797 comma delimited list of cpu numbers, A-B ranges, or 'all'.
799 .BI numa_mem_policy \fR=\fPstr
800 Set this job's memory policy and corresponding NUMA nodes. Format of
804 .B <mode>[:<nodelist>]
807 is one of the following memory policy:
809 .B default, prefer, bind, interleave, local
812 For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is
813 needed to be specified. For \fBprefer\fR, only one node is
814 allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows
815 comma delimited list of numbers, A-B ranges, or 'all'.
817 .BI startdelay \fR=\fPint
818 Delay start of job for the specified number of seconds.
820 .BI runtime \fR=\fPint
821 Terminate processing after the specified number of seconds.
824 If given, run for the specified \fBruntime\fR duration even if the files are
825 completely read or written. The same workload will be repeated as many times
826 as \fBruntime\fR allows.
828 .BI ramp_time \fR=\fPint
829 If set, fio will run the specified workload for this amount of time before
830 logging any performance numbers. Useful for letting performance settle before
831 logging results, thus minimizing the runtime required for stable results. Note
832 that the \fBramp_time\fR is considered lead in time for a job, thus it will
833 increase the total runtime if a special timeout or runtime is specified.
835 .BI invalidate \fR=\fPbool
836 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
839 Use synchronous I/O for buffered writes. For the majority of I/O engines,
840 this means using O_SYNC. Default: false.
842 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
843 Allocation method for I/O unit buffer. Allowed values are:
848 Allocate memory with \fBmalloc\fR\|(3).
851 Use shared memory buffers allocated through \fBshmget\fR\|(2).
854 Same as \fBshm\fR, but use huge pages as backing.
857 Use \fBmmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
858 is given after the option in the format `:\fIfile\fR'.
861 Same as \fBmmap\fR, but use huge files as backing.
864 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
865 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
866 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
867 have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux,
868 huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR
869 and the documentation for that. Normally you just need to echo an appropriate
870 number, eg echoing 8 will ensure that the OS has 8 huge pages ready for
874 .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint
875 This indicates the memory alignment of the IO memory buffers. Note that the
876 given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
877 the alignment of the following buffers are given by the \fBbs\fR used. In
878 other words, if using a \fBbs\fR that is a multiple of the page sized in the
879 system, all buffers will be aligned to this value. If using a \fBbs\fR that
880 is not page aligned, the alignment of subsequent IO memory buffers is the
881 sum of the \fBiomem_align\fR and \fBbs\fR used.
883 .BI hugepage\-size \fR=\fPint
884 Defines the size of a huge page. Must be at least equal to the system setting.
885 Should be a multiple of 1MB. Default: 4MB.
888 Terminate all jobs when one finishes. Default: wait for each job to finish.
890 .BI bwavgtime \fR=\fPint
891 Average bandwidth calculations over the given time in milliseconds. Default:
894 .BI iopsavgtime \fR=\fPint
895 Average IOPS calculations over the given time in milliseconds. Default:
898 .BI create_serialize \fR=\fPbool
899 If true, serialize file creation for the jobs. Default: true.
901 .BI create_fsync \fR=\fPbool
902 \fBfsync\fR\|(2) data file after creation. Default: true.
904 .BI create_on_open \fR=\fPbool
905 If true, the files are not created until they are opened for IO by the job.
907 .BI create_only \fR=\fPbool
908 If true, fio will only run the setup phase of the job. If files need to be
909 laid out or updated on disk, only that will be done. The actual job contents
912 .BI pre_read \fR=\fPbool
913 If this is given, files will be pre-read into memory before starting the given
914 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
915 pointless to pre-read and then drop the cache. This will only work for IO
916 engines that are seekable, since they allow you to read the same data
917 multiple times. Thus it will not work on eg network or splice IO.
919 .BI unlink \fR=\fPbool
920 Unlink job files when done. Default: false.
923 Specifies the number of iterations (runs of the same workload) of this job.
926 .BI do_verify \fR=\fPbool
927 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
930 .BI verify \fR=\fPstr
931 Method of verifying file contents after each iteration of the job. Allowed
936 .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1
937 Store appropriate checksum in the header of each block. crc32c-intel is
938 hardware accelerated SSE4.2 driven, falls back to regular crc32c if
939 not supported by the system.
942 Write extra information about each I/O (timestamp, block number, etc.). The
943 block number is verified. See \fBverify_pattern\fR as well.
946 Pretend to verify. Used for testing internals.
949 This option can be used for repeated burn-in tests of a system to make sure
950 that the written data is also correctly read back. If the data direction given
951 is a read or random read, fio will assume that it should verify a previously
952 written file. If the data direction includes any form of write, the verify will
953 be of the newly written data.
956 .BI verifysort \fR=\fPbool
957 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
958 read them back in a sorted manner. Default: true.
960 .BI verifysort_nr \fR=\fPint
961 Pre-load and sort verify blocks for a read workload.
963 .BI verify_offset \fR=\fPint
964 Swap the verification header with data somewhere else in the block before
965 writing. It is swapped back before verifying.
967 .BI verify_interval \fR=\fPint
968 Write the verification header for this number of bytes, which should divide
969 \fBblocksize\fR. Default: \fBblocksize\fR.
971 .BI verify_pattern \fR=\fPstr
972 If set, fio will fill the io buffers with this pattern. Fio defaults to filling
973 with totally random bytes, but sometimes it's interesting to fill with a known
974 pattern for io verification purposes. Depending on the width of the pattern,
975 fio will fill 1/2/3/4 bytes of the buffer at the time(it can be either a
976 decimal or a hex number). The verify_pattern if larger than a 32-bit quantity
977 has to be a hex number that starts with either "0x" or "0X". Use with
980 .BI verify_fatal \fR=\fPbool
981 If true, exit the job on the first observed verification failure. Default:
984 .BI verify_dump \fR=\fPbool
985 If set, dump the contents of both the original data block and the data block we
986 read off disk to files. This allows later analysis to inspect just what kind of
987 data corruption occurred. Off by default.
989 .BI verify_async \fR=\fPint
990 Fio will normally verify IO inline from the submitting thread. This option
991 takes an integer describing how many async offload threads to create for IO
992 verification instead, causing fio to offload the duty of verifying IO contents
993 to one or more separate threads. If using this offload option, even sync IO
994 engines can benefit from using an \fBiodepth\fR setting higher than 1, as it
995 allows them to have IO in flight while verifies are running.
997 .BI verify_async_cpus \fR=\fPstr
998 Tell fio to set the given CPU affinity on the async IO verification threads.
999 See \fBcpus_allowed\fP for the format used.
1001 .BI verify_backlog \fR=\fPint
1002 Fio will normally verify the written contents of a job that utilizes verify
1003 once that job has completed. In other words, everything is written then
1004 everything is read back and verified. You may want to verify continually
1005 instead for a variety of reasons. Fio stores the meta data associated with an
1006 IO block in memory, so for large verify workloads, quite a bit of memory would
1007 be used up holding this meta data. If this option is enabled, fio will write
1008 only N blocks before verifying these blocks.
1010 .BI verify_backlog_batch \fR=\fPint
1011 Control how many blocks fio will verify if verify_backlog is set. If not set,
1012 will default to the value of \fBverify_backlog\fR (meaning the entire queue is
1013 read back and verified). If \fBverify_backlog_batch\fR is less than
1014 \fBverify_backlog\fR then not all blocks will be verified, if
1015 \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks
1016 will be verified more than once.
1018 .BI trim_percentage \fR=\fPint
1019 Number of verify blocks to discard/trim.
1021 .BI trim_verify_zero \fR=\fPbool
1022 Verify that trim/discarded blocks are returned as zeroes.
1024 .BI trim_backlog \fR=\fPint
1025 Trim after this number of blocks are written.
1027 .BI trim_backlog_batch \fR=\fPint
1028 Trim this number of IO blocks.
1030 .BI experimental_verify \fR=\fPbool
1031 Enable experimental verification.
1033 .B stonewall "\fR,\fP wait_for_previous"
1034 Wait for preceding jobs in the job file to exit before starting this one.
1035 \fBstonewall\fR implies \fBnew_group\fR.
1038 Start a new reporting group. If not given, all jobs in a file will be part
1039 of the same reporting group, unless separated by a stonewall.
1041 .BI numjobs \fR=\fPint
1042 Number of clones (processes/threads performing the same workload) of this job.
1046 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
1050 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
1051 with \fBfork\fR\|(2).
1053 .BI zonesize \fR=\fPint
1054 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
1056 .BI zonerange \fR=\fPint
1057 Give size of an IO zone. See \fBzoneskip\fR.
1059 .BI zoneskip \fR=\fPint
1060 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
1063 .BI write_iolog \fR=\fPstr
1064 Write the issued I/O patterns to the specified file. Specify a separate file
1065 for each job, otherwise the iologs will be interspersed and the file may be
1068 .BI read_iolog \fR=\fPstr
1069 Replay the I/O patterns contained in the specified file generated by
1070 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
1072 .BI replay_no_stall \fR=\fPint
1073 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1074 attempts to respect timing information between I/Os. Enabling
1075 \fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
1076 still respecting ordering.
1078 .BI replay_redirect \fR=\fPstr
1079 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1080 is to replay the IOPS onto the major/minor device that each IOP was recorded
1081 from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
1082 single specified device regardless of the device it was recorded from.
1084 .BI write_bw_log \fR=\fPstr
1085 If given, write a bandwidth log of the jobs in this job file. Can be used to
1086 store data of the bandwidth of the jobs in their lifetime. The included
1087 fio_generate_plots script uses gnuplot to turn these text files into nice
1088 graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
1089 option, the postfix is _bw.log.
1091 .BI write_lat_log \fR=\fPstr
1092 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
1093 filename is given with this option, the default filename of "jobname_type.log"
1094 is used. Even if the filename is given, fio will still append the type of log.
1096 .BI write_iops_log \fR=\fPstr
1097 Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
1098 option, the default filename of "jobname_type.log" is used. Even if the
1099 filename is given, fio will still append the type of log.
1101 .BI log_avg_msec \fR=\fPint
1102 By default, fio will log an entry in the iops, latency, or bw log for every
1103 IO that completes. When writing to the disk log, that can quickly grow to a
1104 very large size. Setting this option makes fio average the each log entry
1105 over the specified period of time, reducing the resolution of the log.
1108 .BI disable_lat \fR=\fPbool
1109 Disable measurements of total latency numbers. Useful only for cutting
1110 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
1111 really high IOPS rates. Note that to really get rid of a large amount of these
1112 calls, this option must be used with disable_slat and disable_bw as well.
1114 .BI disable_clat \fR=\fPbool
1115 Disable measurements of completion latency numbers. See \fBdisable_lat\fR.
1117 .BI disable_slat \fR=\fPbool
1118 Disable measurements of submission latency numbers. See \fBdisable_lat\fR.
1120 .BI disable_bw_measurement \fR=\fPbool
1121 Disable measurements of throughput/bandwidth numbers. See \fBdisable_lat\fR.
1123 .BI lockmem \fR=\fPint
1124 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
1125 simulate a smaller amount of memory. The amount specified is per worker.
1127 .BI exec_prerun \fR=\fPstr
1128 Before running the job, execute the specified command with \fBsystem\fR\|(3).
1130 Output is redirected in a file called \fBjobname.prerun.txt\fR
1133 .BI exec_postrun \fR=\fPstr
1134 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
1136 Output is redirected in a file called \fBjobname.postrun.txt\fR
1139 .BI ioscheduler \fR=\fPstr
1140 Attempt to switch the device hosting the file to the specified I/O scheduler.
1142 .BI cpuload \fR=\fPint
1143 If the job is a CPU cycle-eater, attempt to use the specified percentage of
1146 .BI cpuchunks \fR=\fPint
1147 If the job is a CPU cycle-eater, split the load into cycles of the
1148 given time in milliseconds.
1150 .BI disk_util \fR=\fPbool
1151 Generate disk utilization statistics if the platform supports it. Default: true.
1153 .BI clocksource \fR=\fPstr
1154 Use the given clocksource as the base of timing. The supported options are:
1158 \fBgettimeofday\fR\|(2)
1161 \fBclock_gettime\fR\|(2)
1164 Internal CPU clock source
1168 \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast
1169 (and fio is heavy on time calls). Fio will automatically use this clocksource
1170 if it's supported and considered reliable on the system it is running on,
1171 unless another clocksource is specifically set. For x86/x86-64 CPUs, this
1172 means supporting TSC Invariant.
1174 .BI gtod_reduce \fR=\fPbool
1175 Enable all of the \fBgettimeofday\fR\|(2) reducing options (disable_clat, disable_slat,
1176 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
1177 \fBgettimeofday\fR\|(2) call count. With this option enabled, we only do about 0.4% of
1178 the gtod() calls we would have done if all time keeping was enabled.
1180 .BI gtod_cpu \fR=\fPint
1181 Sometimes it's cheaper to dedicate a single thread of execution to just getting
1182 the current time. Fio (and databases, for instance) are very intensive on
1183 \fBgettimeofday\fR\|(2) calls. With this option, you can set one CPU aside for doing
1184 nothing but logging current time to a shared memory location. Then the other
1185 threads/processes that run IO workloads need only copy that segment, instead of
1186 entering the kernel with a \fBgettimeofday\fR\|(2) call. The CPU set aside for doing
1187 these time calls will be excluded from other uses. Fio will manually clear it
1188 from the CPU mask of other jobs.
1190 .BI ignore_error \fR=\fPstr
1191 Sometimes you want to ignore some errors during test in that case you can specify
1192 error list for each error type.
1194 ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST
1196 errors for given error type is separated with ':'.
1197 Error may be symbol ('ENOSPC', 'ENOMEM') or an integer.
1199 Example: ignore_error=EAGAIN,ENOSPC:122 .
1201 This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE.
1203 .BI error_dump \fR=\fPbool
1204 If set dump every error even if it is non fatal, true by default. If disabled
1205 only fatal error will be dumped
1207 .BI profile \fR=\fPstr
1208 Select a specific builtin performance test.
1210 .BI cgroup \fR=\fPstr
1211 Add job to this control group. If it doesn't exist, it will be created.
1212 The system must have a mounted cgroup blkio mount point for this to work. If
1213 your system doesn't have it mounted, you can do so with:
1215 # mount \-t cgroup \-o blkio none /cgroup
1217 .BI cgroup_weight \fR=\fPint
1218 Set the weight of the cgroup to this value. See the documentation that comes
1219 with the kernel, allowed values are in the range of 100..1000.
1221 .BI cgroup_nodelete \fR=\fPbool
1222 Normally fio will delete the cgroups it has created after the job completion.
1223 To override this behavior and to leave cgroups around after the job completion,
1224 set cgroup_nodelete=1. This can be useful if one wants to inspect various
1225 cgroup files after job completion. Default: false
1228 Instead of running as the invoking user, set the user ID to this value before
1229 the thread/process does any work.
1232 Set group ID, see \fBuid\fR.
1234 .BI unit_base \fR=\fPint
1235 Base unit for reporting. Allowed values are:
1239 Use auto-detection (default).
1249 .BI flow_id \fR=\fPint
1250 The ID of the flow. If not specified, it defaults to being a global flow. See
1254 Weight in token-based flow control. If this value is used, then there is a
1255 \fBflow counter\fR which is used to regulate the proportion of activity between
1256 two or more jobs. fio attempts to keep this flow counter near zero. The
1257 \fBflow\fR parameter stands for how much should be added or subtracted to the
1258 flow counter on each iteration of the main I/O loop. That is, if one job has
1259 \fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly
1260 1:8 ratio in how much one runs vs the other.
1262 .BI flow_watermark \fR=\fPint
1263 The maximum value that the absolute value of the flow counter is allowed to
1264 reach before the job must wait for a lower value of the counter.
1266 .BI flow_sleep \fR=\fPint
1267 The period of time, in microseconds, to wait after the flow watermark has been
1268 exceeded before retrying operations
1270 .BI clat_percentiles \fR=\fPbool
1271 Enable the reporting of percentiles of completion latencies.
1273 .BI percentile_list \fR=\fPfloat_list
1274 Overwrite the default list of percentiles for completion
1275 latencies. Each number is a floating number in the range (0,100], and
1276 the maximum length of the list is 20. Use ':' to separate the
1277 numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
1278 report the values of completion latency below which 99.5% and 99.9% of
1279 the observed latencies fell, respectively.
1280 .SS "Ioengine Parameters List"
1281 Some parameters are only valid when a specific ioengine is in use. These are
1282 used identically to normal parameters, with the caveat that when used on the
1283 command line, the must come after the ioengine that defines them is selected.
1285 .BI (cpu)cpuload \fR=\fPint
1286 Attempt to use the specified percentage of CPU cycles.
1288 .BI (cpu)cpuchunks \fR=\fPint
1289 Split the load into cycles of the given time. In microseconds.
1291 .BI (libaio)userspace_reap
1292 Normally, with the libaio engine in use, fio will use
1293 the io_getevents system call to reap newly returned events.
1294 With this flag turned on, the AIO ring will be read directly
1295 from user-space to reap events. The reaping mode is only
1296 enabled when polling for a minimum of 0 events (eg when
1297 iodepth_batch_complete=0).
1299 .BI (net,netsplice)hostname \fR=\fPstr
1300 The host name or IP address to use for TCP or UDP based IO.
1301 If the job is a TCP listener or UDP reader, the hostname is not
1302 used and must be omitted unless it is a valid UDP multicast address.
1304 .BI (net,netsplice)port \fR=\fPint
1305 The TCP or UDP port to bind to or connect to.
1307 .BI (net,netsplice)interface \fR=\fPstr
1308 The IP address of the network interface used to send or receive UDP multicast
1311 .BI (net,netsplice)ttl \fR=\fPint
1312 Time-to-live value for outgoing UDP multicast packets. Default: 1
1314 .BI (net,netsplice)nodelay \fR=\fPbool
1315 Set TCP_NODELAY on TCP connections.
1317 .BI (net,netsplice)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr
1318 The network protocol to use. Accepted values are:
1323 Transmission control protocol
1326 User datagram protocol
1332 When the protocol is TCP or UDP, the port must also be given,
1333 as well as the hostname if the job is a TCP listener or UDP
1334 reader. For unix sockets, the normal filename option should be
1335 used and the port is invalid.
1338 .BI (net,netsplice)listen
1339 For TCP network connections, tell fio to listen for incoming
1340 connections rather than initiating an outgoing connection. The
1341 hostname must be omitted if this option is used.
1343 .BI (net, pingpong) \fR=\fPbool
1344 Normally a network writer will just continue writing data, and a network reader
1345 will just consume packages. If pingpong=1 is set, a writer will send its normal
1346 payload to the reader, then wait for the reader to send the same payload back.
1347 This allows fio to measure network latencies. The submission and completion
1348 latencies then measure local time spent sending or receiving, and the
1349 completion latency measures how long it took for the other end to receive and
1350 send back. For UDP multicast traffic pingpong=1 should only be set for a single
1351 reader when multiple readers are listening to the same address.
1353 .BI (e4defrag,donorname) \fR=\fPstr
1354 File will be used as a block donor (swap extents between files)
1356 .BI (e4defrag,inplace) \fR=\fPint
1357 Configure donor file block allocation strategy
1360 Preallocate donor's file on init
1363 allocate space immediately inside defragment event, and free right after event
1366 While running, \fBfio\fR will display the status of the created jobs. For
1370 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
1373 The characters in the first set of brackets denote the current status of each
1374 threads. The possible values are:
1380 Setup but not started.
1386 Initialized, waiting.
1389 Running, doing sequential reads.
1392 Running, doing random reads.
1395 Running, doing sequential writes.
1398 Running, doing random writes.
1401 Running, doing mixed sequential reads/writes.
1404 Running, doing mixed random reads/writes.
1407 Running, currently waiting for \fBfsync\fR\|(2).
1410 Running, verifying written data.
1413 Exited, not reaped by main thread.
1416 Exited, thread reaped.
1420 The second set of brackets shows the estimated completion percentage of
1421 the current group. The third set shows the read and write I/O rate,
1422 respectively. Finally, the estimated run time of the job is displayed.
1424 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
1425 for each thread, each group of threads, and each disk, in that order.
1427 Per-thread statistics first show the threads client number, group-id, and
1428 error code. The remaining figures are as follows:
1432 Number of megabytes of I/O performed.
1435 Average data rate (bandwidth).
1441 Submission latency minimum, maximum, average and standard deviation. This is
1442 the time it took to submit the I/O.
1445 Completion latency minimum, maximum, average and standard deviation. This
1446 is the time between submission and completion.
1449 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
1450 and standard deviation.
1453 CPU usage statistics. Includes user and system time, number of context switches
1454 this thread went through and number of major and minor page faults.
1457 Distribution of I/O depths. Each depth includes everything less than (or equal)
1458 to it, but greater than the previous depth.
1461 Number of read/write requests issued, and number of short read/write requests.
1464 Distribution of I/O completion latencies. The numbers follow the same pattern
1468 The group statistics show:
1473 Number of megabytes I/O performed.
1476 Aggregate bandwidth of threads in the group.
1479 Minimum average bandwidth a thread saw.
1482 Maximum average bandwidth a thread saw.
1485 Shortest runtime of threads in the group.
1488 Longest runtime of threads in the group.
1492 Finally, disk statistics are printed with reads first:
1497 Number of I/Os performed by all groups.
1500 Number of merges in the I/O scheduler.
1503 Number of ticks we kept the disk busy.
1506 Total time spent in the disk queue.
1513 It is also possible to get fio to dump the current output while it is
1514 running, without terminating the job. To do that, send fio the \fBUSR1\fR
1517 If the \fB\-\-minimal\fR option is given, the results will be printed in a
1518 semicolon-delimited format suitable for scripted use - a job description
1519 (if provided) follows on a new line. Note that the first
1520 number in the line is the version number. If the output has to be changed
1521 for some reason, this number will be incremented by 1 to signify that
1522 change. The fields are:
1525 .B terse version, fio version, jobname, groupid, error
1529 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1533 .B min, max, mean, standard deviation
1537 .B min, max, mean, standard deviation
1539 Completion latency percentiles (20 fields):
1541 .B Xth percentile=usec
1545 .B min, max, mean, standard deviation
1549 .B min, max, aggregate percentage of total, mean, standard deviation
1555 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1559 .B min, max, mean, standard deviation
1563 .B min, max, mean, standard deviation
1565 Completion latency percentiles (20 fields):
1567 .B Xth percentile=usec
1571 .B min, max, mean, standard deviation
1575 .B min, max, aggregate percentage of total, mean, standard deviation
1581 .B user, system, context switches, major page faults, minor page faults
1584 IO depth distribution:
1586 .B <=1, 2, 4, 8, 16, 32, >=64
1589 IO latency distribution:
1593 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
1597 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
1601 Disk utilization (1 for each disk used):
1603 .B name, read ios, write ios, read merges, write merges, read ticks, write ticks, read in-queue time, write in-queue time, disk utilization percentage
1606 Error Info (dependent on continue_on_error, default off):
1608 .B total # errors, first error code
1611 .B text description (if provided in config - appears on newline)
1614 Normally you would run fio as a stand-alone application on the machine
1615 where the IO workload should be generated. However, it is also possible to
1616 run the frontend and backend of fio separately. This makes it possible to
1617 have a fio server running on the machine(s) where the IO workload should
1618 be running, while controlling it from another machine.
1620 To start the server, you would do:
1622 \fBfio \-\-server=args\fR
1624 on that machine, where args defines what fio listens to. The arguments
1625 are of the form 'type:hostname or IP:port'. 'type' is either 'ip' (or ip4)
1626 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain
1627 socket. 'hostname' is either a hostname or IP address, and 'port' is the port to
1628 listen to (only valid for TCP/IP, not a local socket). Some examples:
1632 Start a fio server, listening on all interfaces on the default port (8765).
1634 2) fio \-\-server=ip:hostname,4444
1636 Start a fio server, listening on IP belonging to hostname and on port 4444.
1638 3) fio \-\-server=ip6:::1,4444
1640 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
1642 4) fio \-\-server=,4444
1644 Start a fio server, listening on all interfaces on port 4444.
1646 5) fio \-\-server=1.2.3.4
1648 Start a fio server, listening on IP 1.2.3.4 on the default port.
1650 6) fio \-\-server=sock:/tmp/fio.sock
1652 Start a fio server, listening on the local socket /tmp/fio.sock.
1654 When a server is running, you can connect to it from a client. The client
1657 fio \-\-local-args \-\-client=server \-\-remote-args <job file(s)>
1659 where \-\-local-args are arguments that are local to the client where it is
1660 running, 'server' is the connect string, and \-\-remote-args and <job file(s)>
1661 are sent to the server. The 'server' string follows the same format as it
1662 does on the server side, to allow IP/hostname/socket and port strings.
1663 You can connect to multiple clients as well, to do that you could run:
1665 fio \-\-client=server2 \-\-client=server2 <job file(s)>
1669 was written by Jens Axboe <jens.axboe@oracle.com>,
1670 now Jens Axboe <jaxboe@fusionio.com>.
1672 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
1673 on documentation by Jens Axboe.
1674 .SH "REPORTING BUGS"
1675 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
1678 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
1680 Sample jobfiles are available in the \fBexamples\fR directory.
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