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 buffered \fR=\fPbool
573 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
576 .BI offset \fR=\fPint
577 Offset in the file to start I/O. Data before the offset will not be touched.
579 .BI offset_increment \fR=\fPint
580 If this is provided, then the real offset becomes the
581 offset + offset_increment * thread_number, where the thread number is a counter
582 that starts at 0 and is incremented for each job. This option is useful if
583 there are several jobs which are intended to operate on a file in parallel in
584 disjoint segments, with even spacing between the starting points.
586 .BI number_ios \fR=\fPint
587 Fio will normally perform IOs until it has exhausted the size of the region
588 set by \fBsize\fR, or if it exhaust the allocated time (or hits an error
589 condition). With this setting, the range/size can be set independently of
590 the number of IOs to perform. When fio reaches this number, it will exit
591 normally and report status.
594 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
595 0, don't sync. Default: 0.
597 .BI fdatasync \fR=\fPint
598 Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the
599 data parts of the file. Default: 0.
601 .BI write_barrier \fR=\fPint
602 Make every Nth write a barrier write.
604 .BI sync_file_range \fR=\fPstr:int
605 Use \fBsync_file_range\fR\|(2) for every \fRval\fP number of write operations. Fio will
606 track range of writes that have happened since the last \fBsync_file_range\fR\|(2) call.
607 \fRstr\fP can currently be one or more of:
611 SYNC_FILE_RANGE_WAIT_BEFORE
614 SYNC_FILE_RANGE_WRITE
617 SYNC_FILE_RANGE_WRITE
621 So if you do sync_file_range=wait_before,write:8, fio would use
622 \fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes.
623 Also see the \fBsync_file_range\fR\|(2) man page. This option is Linux specific.
625 .BI overwrite \fR=\fPbool
626 If writing, setup the file first and do overwrites. Default: false.
628 .BI end_fsync \fR=\fPbool
629 Sync file contents when a write stage has completed. Default: false.
631 .BI fsync_on_close \fR=\fPbool
632 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
633 it will happen on every close, not just at the end of the job. Default: false.
635 .BI rwmixread \fR=\fPint
636 Percentage of a mixed workload that should be reads. Default: 50.
638 .BI rwmixwrite \fR=\fPint
639 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
640 \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two
641 overrides the first. This may interfere with a given rate setting, if fio is
642 asked to limit reads or writes to a certain rate. If that is the case, then
643 the distribution may be skewed. Default: 50.
645 .BI random_distribution \fR=\fPstr:float
646 By default, fio will use a completely uniform random distribution when asked
647 to perform random IO. Sometimes it is useful to skew the distribution in
648 specific ways, ensuring that some parts of the data is more hot than others.
649 Fio includes the following distribution models:
653 Uniform random distribution
663 When using a zipf or pareto distribution, an input value is also needed to
664 define the access pattern. For zipf, this is the zipf theta. For pareto,
665 it's the pareto power. Fio includes a test program, genzipf, that can be
666 used visualize what the given input values will yield in terms of hit rates.
667 If you wanted to use zipf with a theta of 1.2, you would use
668 random_distribution=zipf:1.2 as the option. If a non-uniform model is used,
669 fio will disable use of the random map.
671 .BI percentage_random \fR=\fPint
672 For a random workload, set how big a percentage should be random. This defaults
673 to 100%, in which case the workload is fully random. It can be set from
674 anywhere from 0 to 100. Setting it to 0 would make the workload fully
675 sequential. It is possible to set different values for reads, writes, and
676 trim. To do so, simply use a comma separated list. See \fBblocksize\fR.
679 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
680 this parameter is given, a new offset will be chosen without looking at past
681 I/O history. This parameter is mutually exclusive with \fBverify\fR.
683 .BI softrandommap \fR=\fPbool
684 See \fBnorandommap\fR. If fio runs with the random block map enabled and it
685 fails to allocate the map, if this option is set it will continue without a
686 random block map. As coverage will not be as complete as with random maps, this
687 option is disabled by default.
689 .BI random_generator \fR=\fPstr
690 Fio supports the following engines for generating IO offsets for random IO:
694 Strong 2^88 cycle random number generator
697 Linear feedback shift register generator
701 Tausworthe is a strong random number generator, but it requires tracking on the
702 side if we want to ensure that blocks are only read or written once. LFSR
703 guarantees that we never generate the same offset twice, and it's also less
704 computationally expensive. It's not a true random generator, however, though
705 for IO purposes it's typically good enough. LFSR only works with single block
706 sizes, not with workloads that use multiple block sizes. If used with such a
707 workload, fio may read or write some blocks multiple times.
710 Run job with given nice value. See \fBnice\fR\|(2).
713 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
716 .BI prioclass \fR=\fPint
717 Set I/O priority class. See \fBionice\fR\|(1).
719 .BI thinktime \fR=\fPint
720 Stall job for given number of microseconds between issuing I/Os.
722 .BI thinktime_spin \fR=\fPint
723 Pretend to spend CPU time for given number of microseconds, sleeping the rest
724 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
726 .BI thinktime_blocks \fR=\fPint
727 Only valid if thinktime is set - control how many blocks to issue, before
728 waiting \fBthinktime\fR microseconds. If not set, defaults to 1 which will
729 make fio wait \fBthinktime\fR microseconds after every block. This
730 effectively makes any queue depth setting redundant, since no more than 1 IO
731 will be queued before we have to complete it and do our thinktime. In other
732 words, this setting effectively caps the queue depth if the latter is larger.
736 Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix
737 rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each,
738 or you can specify read and writes separately. Using \fBrate\fR=1m,500k would
739 limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes
740 can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only
741 limit writes (to 500KB/sec), the latter will only limit reads.
743 .BI ratemin \fR=\fPint
744 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
745 Failing to meet this requirement will cause the job to exit. The same format
746 as \fBrate\fR is used for read vs write separation.
748 .BI rate_iops \fR=\fPint
749 Cap the bandwidth to this number of IOPS. Basically the same as rate, just
750 specified independently of bandwidth. The same format as \fBrate\fR is used for
751 read vs write separation. If \fBblocksize\fR is a range, the smallest block
752 size is used as the metric.
754 .BI rate_iops_min \fR=\fPint
755 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
756 is used for read vs write separation.
758 .BI ratecycle \fR=\fPint
759 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
760 milliseconds. Default: 1000ms.
762 .BI max_latency \fR=\fPint
763 If set, fio will exit the job if it exceeds this maximum latency. It will exit
766 .BI cpumask \fR=\fPint
767 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
768 may run on. See \fBsched_setaffinity\fR\|(2).
770 .BI cpus_allowed \fR=\fPstr
771 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
773 .BI numa_cpu_nodes \fR=\fPstr
774 Set this job running on specified NUMA nodes' CPUs. The arguments allow
775 comma delimited list of cpu numbers, A-B ranges, or 'all'.
777 .BI numa_mem_policy \fR=\fPstr
778 Set this job's memory policy and corresponding NUMA nodes. Format of
782 .B <mode>[:<nodelist>]
785 is one of the following memory policy:
787 .B default, prefer, bind, interleave, local
790 For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is
791 needed to be specified. For \fBprefer\fR, only one node is
792 allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows
793 comma delimited list of numbers, A-B ranges, or 'all'.
795 .BI startdelay \fR=\fPint
796 Delay start of job for the specified number of seconds.
798 .BI runtime \fR=\fPint
799 Terminate processing after the specified number of seconds.
802 If given, run for the specified \fBruntime\fR duration even if the files are
803 completely read or written. The same workload will be repeated as many times
804 as \fBruntime\fR allows.
806 .BI ramp_time \fR=\fPint
807 If set, fio will run the specified workload for this amount of time before
808 logging any performance numbers. Useful for letting performance settle before
809 logging results, thus minimizing the runtime required for stable results. Note
810 that the \fBramp_time\fR is considered lead in time for a job, thus it will
811 increase the total runtime if a special timeout or runtime is specified.
813 .BI invalidate \fR=\fPbool
814 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
817 Use synchronous I/O for buffered writes. For the majority of I/O engines,
818 this means using O_SYNC. Default: false.
820 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
821 Allocation method for I/O unit buffer. Allowed values are:
826 Allocate memory with \fBmalloc\fR\|(3).
829 Use shared memory buffers allocated through \fBshmget\fR\|(2).
832 Same as \fBshm\fR, but use huge pages as backing.
835 Use \fBmmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
836 is given after the option in the format `:\fIfile\fR'.
839 Same as \fBmmap\fR, but use huge files as backing.
842 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
843 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
844 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
845 have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux,
846 huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR
847 and the documentation for that. Normally you just need to echo an appropriate
848 number, eg echoing 8 will ensure that the OS has 8 huge pages ready for
852 .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint
853 This indicates the memory alignment of the IO memory buffers. Note that the
854 given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
855 the alignment of the following buffers are given by the \fBbs\fR used. In
856 other words, if using a \fBbs\fR that is a multiple of the page sized in the
857 system, all buffers will be aligned to this value. If using a \fBbs\fR that
858 is not page aligned, the alignment of subsequent IO memory buffers is the
859 sum of the \fBiomem_align\fR and \fBbs\fR used.
861 .BI hugepage\-size \fR=\fPint
862 Defines the size of a huge page. Must be at least equal to the system setting.
863 Should be a multiple of 1MB. Default: 4MB.
866 Terminate all jobs when one finishes. Default: wait for each job to finish.
868 .BI bwavgtime \fR=\fPint
869 Average bandwidth calculations over the given time in milliseconds. Default:
872 .BI iopsavgtime \fR=\fPint
873 Average IOPS calculations over the given time in milliseconds. Default:
876 .BI create_serialize \fR=\fPbool
877 If true, serialize file creation for the jobs. Default: true.
879 .BI create_fsync \fR=\fPbool
880 \fBfsync\fR\|(2) data file after creation. Default: true.
882 .BI create_on_open \fR=\fPbool
883 If true, the files are not created until they are opened for IO by the job.
885 .BI create_only \fR=\fPbool
886 If true, fio will only run the setup phase of the job. If files need to be
887 laid out or updated on disk, only that will be done. The actual job contents
890 .BI pre_read \fR=\fPbool
891 If this is given, files will be pre-read into memory before starting the given
892 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
893 pointless to pre-read and then drop the cache. This will only work for IO
894 engines that are seekable, since they allow you to read the same data
895 multiple times. Thus it will not work on eg network or splice IO.
897 .BI unlink \fR=\fPbool
898 Unlink job files when done. Default: false.
901 Specifies the number of iterations (runs of the same workload) of this job.
904 .BI do_verify \fR=\fPbool
905 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
908 .BI verify \fR=\fPstr
909 Method of verifying file contents after each iteration of the job. Allowed
914 .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1
915 Store appropriate checksum in the header of each block. crc32c-intel is
916 hardware accelerated SSE4.2 driven, falls back to regular crc32c if
917 not supported by the system.
920 Write extra information about each I/O (timestamp, block number, etc.). The
921 block number is verified. See \fBverify_pattern\fR as well.
924 Pretend to verify. Used for testing internals.
927 This option can be used for repeated burn-in tests of a system to make sure
928 that the written data is also correctly read back. If the data direction given
929 is a read or random read, fio will assume that it should verify a previously
930 written file. If the data direction includes any form of write, the verify will
931 be of the newly written data.
934 .BI verifysort \fR=\fPbool
935 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
936 read them back in a sorted manner. Default: true.
938 .BI verifysort_nr \fR=\fPint
939 Pre-load and sort verify blocks for a read workload.
941 .BI verify_offset \fR=\fPint
942 Swap the verification header with data somewhere else in the block before
943 writing. It is swapped back before verifying.
945 .BI verify_interval \fR=\fPint
946 Write the verification header for this number of bytes, which should divide
947 \fBblocksize\fR. Default: \fBblocksize\fR.
949 .BI verify_pattern \fR=\fPstr
950 If set, fio will fill the io buffers with this pattern. Fio defaults to filling
951 with totally random bytes, but sometimes it's interesting to fill with a known
952 pattern for io verification purposes. Depending on the width of the pattern,
953 fio will fill 1/2/3/4 bytes of the buffer at the time(it can be either a
954 decimal or a hex number). The verify_pattern if larger than a 32-bit quantity
955 has to be a hex number that starts with either "0x" or "0X". Use with
958 .BI verify_fatal \fR=\fPbool
959 If true, exit the job on the first observed verification failure. Default:
962 .BI verify_dump \fR=\fPbool
963 If set, dump the contents of both the original data block and the data block we
964 read off disk to files. This allows later analysis to inspect just what kind of
965 data corruption occurred. Off by default.
967 .BI verify_async \fR=\fPint
968 Fio will normally verify IO inline from the submitting thread. This option
969 takes an integer describing how many async offload threads to create for IO
970 verification instead, causing fio to offload the duty of verifying IO contents
971 to one or more separate threads. If using this offload option, even sync IO
972 engines can benefit from using an \fBiodepth\fR setting higher than 1, as it
973 allows them to have IO in flight while verifies are running.
975 .BI verify_async_cpus \fR=\fPstr
976 Tell fio to set the given CPU affinity on the async IO verification threads.
977 See \fBcpus_allowed\fP for the format used.
979 .BI verify_backlog \fR=\fPint
980 Fio will normally verify the written contents of a job that utilizes verify
981 once that job has completed. In other words, everything is written then
982 everything is read back and verified. You may want to verify continually
983 instead for a variety of reasons. Fio stores the meta data associated with an
984 IO block in memory, so for large verify workloads, quite a bit of memory would
985 be used up holding this meta data. If this option is enabled, fio will write
986 only N blocks before verifying these blocks.
988 .BI verify_backlog_batch \fR=\fPint
989 Control how many blocks fio will verify if verify_backlog is set. If not set,
990 will default to the value of \fBverify_backlog\fR (meaning the entire queue is
991 read back and verified). If \fBverify_backlog_batch\fR is less than
992 \fBverify_backlog\fR then not all blocks will be verified, if
993 \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks
994 will be verified more than once.
996 .BI trim_percentage \fR=\fPint
997 Number of verify blocks to discard/trim.
999 .BI trim_verify_zero \fR=\fPbool
1000 Verify that trim/discarded blocks are returned as zeroes.
1002 .BI trim_backlog \fR=\fPint
1003 Trim after this number of blocks are written.
1005 .BI trim_backlog_batch \fR=\fPint
1006 Trim this number of IO blocks.
1008 .BI experimental_verify \fR=\fPbool
1009 Enable experimental verification.
1011 .B stonewall "\fR,\fP wait_for_previous"
1012 Wait for preceding jobs in the job file to exit before starting this one.
1013 \fBstonewall\fR implies \fBnew_group\fR.
1016 Start a new reporting group. If not given, all jobs in a file will be part
1017 of the same reporting group, unless separated by a stonewall.
1019 .BI numjobs \fR=\fPint
1020 Number of clones (processes/threads performing the same workload) of this job.
1024 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
1028 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
1029 with \fBfork\fR\|(2).
1031 .BI zonesize \fR=\fPint
1032 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
1034 .BI zonerange \fR=\fPint
1035 Give size of an IO zone. See \fBzoneskip\fR.
1037 .BI zoneskip \fR=\fPint
1038 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
1041 .BI write_iolog \fR=\fPstr
1042 Write the issued I/O patterns to the specified file. Specify a separate file
1043 for each job, otherwise the iologs will be interspersed and the file may be
1046 .BI read_iolog \fR=\fPstr
1047 Replay the I/O patterns contained in the specified file generated by
1048 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
1050 .BI replay_no_stall \fR=\fPint
1051 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1052 attempts to respect timing information between I/Os. Enabling
1053 \fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
1054 still respecting ordering.
1056 .BI replay_redirect \fR=\fPstr
1057 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1058 is to replay the IOPS onto the major/minor device that each IOP was recorded
1059 from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
1060 single specified device regardless of the device it was recorded from.
1062 .BI write_bw_log \fR=\fPstr
1063 If given, write a bandwidth log of the jobs in this job file. Can be used to
1064 store data of the bandwidth of the jobs in their lifetime. The included
1065 fio_generate_plots script uses gnuplot to turn these text files into nice
1066 graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
1067 option, the postfix is _bw.log.
1069 .BI write_lat_log \fR=\fPstr
1070 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
1071 filename is given with this option, the default filename of "jobname_type.log"
1072 is used. Even if the filename is given, fio will still append the type of log.
1074 .BI write_iops_log \fR=\fPstr
1075 Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
1076 option, the default filename of "jobname_type.log" is used. Even if the
1077 filename is given, fio will still append the type of log.
1079 .BI log_avg_msec \fR=\fPint
1080 By default, fio will log an entry in the iops, latency, or bw log for every
1081 IO that completes. When writing to the disk log, that can quickly grow to a
1082 very large size. Setting this option makes fio average the each log entry
1083 over the specified period of time, reducing the resolution of the log.
1086 .BI disable_lat \fR=\fPbool
1087 Disable measurements of total latency numbers. Useful only for cutting
1088 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
1089 really high IOPS rates. Note that to really get rid of a large amount of these
1090 calls, this option must be used with disable_slat and disable_bw as well.
1092 .BI disable_clat \fR=\fPbool
1093 Disable measurements of completion latency numbers. See \fBdisable_lat\fR.
1095 .BI disable_slat \fR=\fPbool
1096 Disable measurements of submission latency numbers. See \fBdisable_lat\fR.
1098 .BI disable_bw_measurement \fR=\fPbool
1099 Disable measurements of throughput/bandwidth numbers. See \fBdisable_lat\fR.
1101 .BI lockmem \fR=\fPint
1102 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
1103 simulate a smaller amount of memory. The amount specified is per worker.
1105 .BI exec_prerun \fR=\fPstr
1106 Before running the job, execute the specified command with \fBsystem\fR\|(3).
1108 Output is redirected in a file called \fBjobname.prerun.txt\fR
1111 .BI exec_postrun \fR=\fPstr
1112 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
1114 Output is redirected in a file called \fBjobname.postrun.txt\fR
1117 .BI ioscheduler \fR=\fPstr
1118 Attempt to switch the device hosting the file to the specified I/O scheduler.
1120 .BI cpuload \fR=\fPint
1121 If the job is a CPU cycle-eater, attempt to use the specified percentage of
1124 .BI cpuchunks \fR=\fPint
1125 If the job is a CPU cycle-eater, split the load into cycles of the
1126 given time in milliseconds.
1128 .BI disk_util \fR=\fPbool
1129 Generate disk utilization statistics if the platform supports it. Default: true.
1131 .BI clocksource \fR=\fPstr
1132 Use the given clocksource as the base of timing. The supported options are:
1136 \fBgettimeofday\fR\|(2)
1139 \fBclock_gettime\fR\|(2)
1142 Internal CPU clock source
1146 \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast
1147 (and fio is heavy on time calls). Fio will automatically use this clocksource
1148 if it's supported and considered reliable on the system it is running on,
1149 unless another clocksource is specifically set. For x86/x86-64 CPUs, this
1150 means supporting TSC Invariant.
1152 .BI gtod_reduce \fR=\fPbool
1153 Enable all of the \fBgettimeofday\fR\|(2) reducing options (disable_clat, disable_slat,
1154 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
1155 \fBgettimeofday\fR\|(2) call count. With this option enabled, we only do about 0.4% of
1156 the gtod() calls we would have done if all time keeping was enabled.
1158 .BI gtod_cpu \fR=\fPint
1159 Sometimes it's cheaper to dedicate a single thread of execution to just getting
1160 the current time. Fio (and databases, for instance) are very intensive on
1161 \fBgettimeofday\fR\|(2) calls. With this option, you can set one CPU aside for doing
1162 nothing but logging current time to a shared memory location. Then the other
1163 threads/processes that run IO workloads need only copy that segment, instead of
1164 entering the kernel with a \fBgettimeofday\fR\|(2) call. The CPU set aside for doing
1165 these time calls will be excluded from other uses. Fio will manually clear it
1166 from the CPU mask of other jobs.
1168 .BI ignore_error \fR=\fPstr
1169 Sometimes you want to ignore some errors during test in that case you can specify
1170 error list for each error type.
1172 ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST
1174 errors for given error type is separated with ':'.
1175 Error may be symbol ('ENOSPC', 'ENOMEM') or an integer.
1177 Example: ignore_error=EAGAIN,ENOSPC:122 .
1179 This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE.
1181 .BI error_dump \fR=\fPbool
1182 If set dump every error even if it is non fatal, true by default. If disabled
1183 only fatal error will be dumped
1185 .BI profile \fR=\fPstr
1186 Select a specific builtin performance test.
1188 .BI cgroup \fR=\fPstr
1189 Add job to this control group. If it doesn't exist, it will be created.
1190 The system must have a mounted cgroup blkio mount point for this to work. If
1191 your system doesn't have it mounted, you can do so with:
1193 # mount \-t cgroup \-o blkio none /cgroup
1195 .BI cgroup_weight \fR=\fPint
1196 Set the weight of the cgroup to this value. See the documentation that comes
1197 with the kernel, allowed values are in the range of 100..1000.
1199 .BI cgroup_nodelete \fR=\fPbool
1200 Normally fio will delete the cgroups it has created after the job completion.
1201 To override this behavior and to leave cgroups around after the job completion,
1202 set cgroup_nodelete=1. This can be useful if one wants to inspect various
1203 cgroup files after job completion. Default: false
1206 Instead of running as the invoking user, set the user ID to this value before
1207 the thread/process does any work.
1210 Set group ID, see \fBuid\fR.
1212 .BI unit_base \fR=\fPint
1213 Base unit for reporting. Allowed values are:
1217 Use auto-detection (default).
1227 .BI flow_id \fR=\fPint
1228 The ID of the flow. If not specified, it defaults to being a global flow. See
1232 Weight in token-based flow control. If this value is used, then there is a
1233 \fBflow counter\fR which is used to regulate the proportion of activity between
1234 two or more jobs. fio attempts to keep this flow counter near zero. The
1235 \fBflow\fR parameter stands for how much should be added or subtracted to the
1236 flow counter on each iteration of the main I/O loop. That is, if one job has
1237 \fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly
1238 1:8 ratio in how much one runs vs the other.
1240 .BI flow_watermark \fR=\fPint
1241 The maximum value that the absolute value of the flow counter is allowed to
1242 reach before the job must wait for a lower value of the counter.
1244 .BI flow_sleep \fR=\fPint
1245 The period of time, in microseconds, to wait after the flow watermark has been
1246 exceeded before retrying operations
1248 .BI clat_percentiles \fR=\fPbool
1249 Enable the reporting of percentiles of completion latencies.
1251 .BI percentile_list \fR=\fPfloat_list
1252 Overwrite the default list of percentiles for completion
1253 latencies. Each number is a floating number in the range (0,100], and
1254 the maximum length of the list is 20. Use ':' to separate the
1255 numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
1256 report the values of completion latency below which 99.5% and 99.9% of
1257 the observed latencies fell, respectively.
1258 .SS "Ioengine Parameters List"
1259 Some parameters are only valid when a specific ioengine is in use. These are
1260 used identically to normal parameters, with the caveat that when used on the
1261 command line, the must come after the ioengine that defines them is selected.
1263 .BI (cpu)cpuload \fR=\fPint
1264 Attempt to use the specified percentage of CPU cycles.
1266 .BI (cpu)cpuchunks \fR=\fPint
1267 Split the load into cycles of the given time. In microseconds.
1269 .BI (libaio)userspace_reap
1270 Normally, with the libaio engine in use, fio will use
1271 the io_getevents system call to reap newly returned events.
1272 With this flag turned on, the AIO ring will be read directly
1273 from user-space to reap events. The reaping mode is only
1274 enabled when polling for a minimum of 0 events (eg when
1275 iodepth_batch_complete=0).
1277 .BI (net,netsplice)hostname \fR=\fPstr
1278 The host name or IP address to use for TCP or UDP based IO.
1279 If the job is a TCP listener or UDP reader, the hostname is not
1280 used and must be omitted unless it is a valid UDP multicast address.
1282 .BI (net,netsplice)port \fR=\fPint
1283 The TCP or UDP port to bind to or connect to.
1285 .BI (net,netsplice)interface \fR=\fPstr
1286 The IP address of the network interface used to send or receive UDP multicast
1289 .BI (net,netsplice)ttl \fR=\fPint
1290 Time-to-live value for outgoing UDP multicast packets. Default: 1
1292 .BI (net,netsplice)nodelay \fR=\fPbool
1293 Set TCP_NODELAY on TCP connections.
1295 .BI (net,netsplice)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr
1296 The network protocol to use. Accepted values are:
1301 Transmission control protocol
1304 User datagram protocol
1310 When the protocol is TCP or UDP, the port must also be given,
1311 as well as the hostname if the job is a TCP listener or UDP
1312 reader. For unix sockets, the normal filename option should be
1313 used and the port is invalid.
1316 .BI (net,netsplice)listen
1317 For TCP network connections, tell fio to listen for incoming
1318 connections rather than initiating an outgoing connection. The
1319 hostname must be omitted if this option is used.
1321 .BI (net, pingpong) \fR=\fPbool
1322 Normally a network writer will just continue writing data, and a network reader
1323 will just consume packages. If pingpong=1 is set, a writer will send its normal
1324 payload to the reader, then wait for the reader to send the same payload back.
1325 This allows fio to measure network latencies. The submission and completion
1326 latencies then measure local time spent sending or receiving, and the
1327 completion latency measures how long it took for the other end to receive and
1328 send back. For UDP multicast traffic pingpong=1 should only be set for a single
1329 reader when multiple readers are listening to the same address.
1331 .BI (e4defrag,donorname) \fR=\fPstr
1332 File will be used as a block donor (swap extents between files)
1334 .BI (e4defrag,inplace) \fR=\fPint
1335 Configure donor file block allocation strategy
1338 Preallocate donor's file on init
1341 allocate space immediately inside defragment event, and free right after event
1344 While running, \fBfio\fR will display the status of the created jobs. For
1348 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
1351 The characters in the first set of brackets denote the current status of each
1352 threads. The possible values are:
1358 Setup but not started.
1364 Initialized, waiting.
1367 Running, doing sequential reads.
1370 Running, doing random reads.
1373 Running, doing sequential writes.
1376 Running, doing random writes.
1379 Running, doing mixed sequential reads/writes.
1382 Running, doing mixed random reads/writes.
1385 Running, currently waiting for \fBfsync\fR\|(2).
1388 Running, verifying written data.
1391 Exited, not reaped by main thread.
1394 Exited, thread reaped.
1398 The second set of brackets shows the estimated completion percentage of
1399 the current group. The third set shows the read and write I/O rate,
1400 respectively. Finally, the estimated run time of the job is displayed.
1402 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
1403 for each thread, each group of threads, and each disk, in that order.
1405 Per-thread statistics first show the threads client number, group-id, and
1406 error code. The remaining figures are as follows:
1410 Number of megabytes of I/O performed.
1413 Average data rate (bandwidth).
1419 Submission latency minimum, maximum, average and standard deviation. This is
1420 the time it took to submit the I/O.
1423 Completion latency minimum, maximum, average and standard deviation. This
1424 is the time between submission and completion.
1427 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
1428 and standard deviation.
1431 CPU usage statistics. Includes user and system time, number of context switches
1432 this thread went through and number of major and minor page faults.
1435 Distribution of I/O depths. Each depth includes everything less than (or equal)
1436 to it, but greater than the previous depth.
1439 Number of read/write requests issued, and number of short read/write requests.
1442 Distribution of I/O completion latencies. The numbers follow the same pattern
1446 The group statistics show:
1451 Number of megabytes I/O performed.
1454 Aggregate bandwidth of threads in the group.
1457 Minimum average bandwidth a thread saw.
1460 Maximum average bandwidth a thread saw.
1463 Shortest runtime of threads in the group.
1466 Longest runtime of threads in the group.
1470 Finally, disk statistics are printed with reads first:
1475 Number of I/Os performed by all groups.
1478 Number of merges in the I/O scheduler.
1481 Number of ticks we kept the disk busy.
1484 Total time spent in the disk queue.
1491 It is also possible to get fio to dump the current output while it is
1492 running, without terminating the job. To do that, send fio the \fBUSR1\fR
1495 If the \fB\-\-minimal\fR option is given, the results will be printed in a
1496 semicolon-delimited format suitable for scripted use - a job description
1497 (if provided) follows on a new line. Note that the first
1498 number in the line is the version number. If the output has to be changed
1499 for some reason, this number will be incremented by 1 to signify that
1500 change. The fields are:
1503 .B terse version, fio version, jobname, groupid, error
1507 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1511 .B min, max, mean, standard deviation
1515 .B min, max, mean, standard deviation
1517 Completion latency percentiles (20 fields):
1519 .B Xth percentile=usec
1523 .B min, max, mean, standard deviation
1527 .B min, max, aggregate percentage of total, mean, standard deviation
1533 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1537 .B min, max, mean, standard deviation
1541 .B min, max, mean, standard deviation
1543 Completion latency percentiles (20 fields):
1545 .B Xth percentile=usec
1549 .B min, max, mean, standard deviation
1553 .B min, max, aggregate percentage of total, mean, standard deviation
1559 .B user, system, context switches, major page faults, minor page faults
1562 IO depth distribution:
1564 .B <=1, 2, 4, 8, 16, 32, >=64
1567 IO latency distribution:
1571 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
1575 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
1579 Disk utilization (1 for each disk used):
1581 .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
1584 Error Info (dependent on continue_on_error, default off):
1586 .B total # errors, first error code
1589 .B text description (if provided in config - appears on newline)
1592 Normally you would run fio as a stand-alone application on the machine
1593 where the IO workload should be generated. However, it is also possible to
1594 run the frontend and backend of fio separately. This makes it possible to
1595 have a fio server running on the machine(s) where the IO workload should
1596 be running, while controlling it from another machine.
1598 To start the server, you would do:
1600 \fBfio \-\-server=args\fR
1602 on that machine, where args defines what fio listens to. The arguments
1603 are of the form 'type:hostname or IP:port'. 'type' is either 'ip' (or ip4)
1604 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain
1605 socket. 'hostname' is either a hostname or IP address, and 'port' is the port to
1606 listen to (only valid for TCP/IP, not a local socket). Some examples:
1610 Start a fio server, listening on all interfaces on the default port (8765).
1612 2) fio \-\-server=ip:hostname,4444
1614 Start a fio server, listening on IP belonging to hostname and on port 4444.
1616 3) fio \-\-server=ip6:::1,4444
1618 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
1620 4) fio \-\-server=,4444
1622 Start a fio server, listening on all interfaces on port 4444.
1624 5) fio \-\-server=1.2.3.4
1626 Start a fio server, listening on IP 1.2.3.4 on the default port.
1628 6) fio \-\-server=sock:/tmp/fio.sock
1630 Start a fio server, listening on the local socket /tmp/fio.sock.
1632 When a server is running, you can connect to it from a client. The client
1635 fio \-\-local-args \-\-client=server \-\-remote-args <job file(s)>
1637 where \-\-local-args are arguments that are local to the client where it is
1638 running, 'server' is the connect string, and \-\-remote-args and <job file(s)>
1639 are sent to the server. The 'server' string follows the same format as it
1640 does on the server side, to allow IP/hostname/socket and port strings.
1641 You can connect to multiple clients as well, to do that you could run:
1643 fio \-\-client=server2 \-\-client=server2 <job file(s)>
1647 was written by Jens Axboe <jens.axboe@oracle.com>,
1648 now Jens Axboe <jaxboe@fusionio.com>.
1650 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
1651 on documentation by Jens Axboe.
1652 .SH "REPORTING BUGS"
1653 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
1656 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
1658 Sample jobfiles are available in the \fBexamples\fR directory.
projects / fio.git / blob