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 Print statistics in selected mode AND terse, semicolon-delimited format.
39 Display version information and exit.
41 .BI \-\-terse\-version \fR=\fPversion
42 Set terse version output format (Current version 3, or older version 2).
45 Display usage information and exit.
48 Perform test and validation of internal CPU clock
50 .BI \-\-crctest[\fR=\fPtest]
51 Test the speed of the builtin checksumming functions. If no argument is given,
52 all of them are tested. Or a comma separated list can be passed, in which
53 case the given ones are tested.
55 .BI \-\-cmdhelp \fR=\fPcommand
56 Print help information for \fIcommand\fR. May be `all' for all commands.
58 .BI \-\-enghelp \fR=\fPioengine[,command]
59 List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR defined by \fIioengine\fR.
61 .BI \-\-showcmd \fR=\fPjobfile
62 Convert \fIjobfile\fR to a set of command-line options.
64 .BI \-\-eta \fR=\fPwhen
65 Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
66 be one of `always', `never' or `auto'.
68 .BI \-\-eta\-newline \fR=\fPtime
69 Force an ETA newline for every `time` period passed.
71 .BI \-\-status\-interval \fR=\fPtime
72 Report full output status every `time` period passed.
75 Turn on safety read-only checks, preventing any attempted write.
77 .BI \-\-section \fR=\fPsec
78 Only run section \fIsec\fR from job file. Multiple of these options can be given, adding more sections to run.
80 .BI \-\-alloc\-size \fR=\fPkb
81 Set the internal smalloc pool size to \fIkb\fP kilobytes.
83 .BI \-\-warnings\-fatal
84 All fio parser warnings are fatal, causing fio to exit with an error.
86 .BI \-\-max\-jobs \fR=\fPnr
87 Set the maximum allowed number of jobs (threads/processes) to support.
89 .BI \-\-server \fR=\fPargs
90 Start a backend server, with \fIargs\fP specifying what to listen to. See client/server section.
92 .BI \-\-daemonize \fR=\fPpidfile
93 Background a fio server, writing the pid to the given pid file.
95 .BI \-\-client \fR=\fPhost
96 Instead of running the jobs locally, send and run them on the given host.
98 .BI \-\-idle\-prof \fR=\fPoption
99 Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate).
100 .SH "JOB FILE FORMAT"
101 Job files are in `ini' format. They consist of one or more
102 job definitions, which begin with a job name in square brackets and
103 extend to the next job name. The job name can be any ASCII string
104 except `global', which has a special meaning. Following the job name is
105 a sequence of zero or more parameters, one per line, that define the
106 behavior of the job. Any line starting with a `;' or `#' character is
107 considered a comment and ignored.
109 If \fIjobfile\fR is specified as `-', the job file will be read from
112 The global section contains default parameters for jobs specified in the
113 job file. A job is only affected by global sections residing above it,
114 and there may be any number of global sections. Specific job definitions
115 may override any parameter set in global sections.
118 Some parameters may take arguments of a specific type. The types used are:
121 String: a sequence of alphanumeric characters.
124 SI integer: a whole number, possibly containing a suffix denoting the base unit
125 of the value. Accepted suffixes are `k', 'M', 'G', 'T', and 'P', denoting
126 kilo (1024), mega (1024^2), giga (1024^3), tera (1024^4), and peta (1024^5)
127 respectively. If prefixed with '0x', the value is assumed to be base 16
128 (hexadecimal). A suffix may include a trailing 'b', for instance 'kb' is
129 identical to 'k'. You can specify a base 10 value by using 'KiB', 'MiB','GiB',
130 etc. This is useful for disk drives where values are often given in base 10
131 values. Specifying '30GiB' will get you 30*1000^3 bytes.
132 When specifying times the default suffix meaning changes, still denoting the
133 base unit of the value, but accepted suffixes are 'D' (days), 'H' (hours), 'M'
134 (minutes), 'S' Seconds, 'ms' (or msec) milli seconds, 'us' (or 'usec') micro
135 seconds. Time values without a unit specify seconds.
136 The suffixes are not case sensitive.
139 Boolean: a true or false value. `0' denotes false, `1' denotes true.
142 Integer range: a range of integers specified in the format
143 \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and
144 \fIupper\fR may contain a suffix as described above. If an option allows two
145 sets of ranges, they are separated with a `,' or `/' character. For example:
149 List of floating numbers: A list of floating numbers, separated by
154 May be used to override the job name. On the command line, this parameter
155 has the special purpose of signalling the start of a new job.
157 .BI description \fR=\fPstr
158 Human-readable description of the job. It is printed when the job is run, but
159 otherwise has no special purpose.
161 .BI directory \fR=\fPstr
162 Prefix filenames with this directory. Used to place files in a location other
164 You can specify a number of directories by separating the names with a ':'
165 character. These directories will be assigned equally distributed to job clones
166 creates with \fInumjobs\fR as long as they are using generated filenames.
167 If specific \fIfilename(s)\fR are set fio will use the first listed directory,
168 and thereby matching the \fIfilename\fR semantic which generates a file each
169 clone if not specified, but let all clones use the same if set. See
170 \fIfilename\fR for considerations regarding escaping certain characters on
173 .BI filename \fR=\fPstr
175 normally makes up a file name based on the job name, thread number, and file
176 number. If you want to share files between threads in a job or several jobs,
177 specify a \fIfilename\fR for each of them to override the default.
178 If the I/O engine is file-based, you can specify
179 a number of files by separating the names with a `:' character. `\-' is a
180 reserved name, meaning stdin or stdout, depending on the read/write direction
181 set. On Windows, disk devices are accessed as \\.\PhysicalDrive0 for the first
182 device, \\.\PhysicalDrive1 for the second etc. Note: Windows and FreeBSD
183 prevent write access to areas of the disk containing in-use data
184 (e.g. filesystems). If the wanted filename does need to include a colon, then
185 escape that with a '\' character. For instance, if the filename is
186 "/dev/dsk/foo@3,0:c", then you would use filename="/dev/dsk/foo@3,0\:c".
188 .BI filename_format \fR=\fPstr
189 If sharing multiple files between jobs, it is usually necessary to have
190 fio generate the exact names that you want. By default, fio will name a file
191 based on the default file format specification of
192 \fBjobname.jobnumber.filenumber\fP. With this option, that can be
193 customized. Fio will recognize and replace the following keywords in this
199 The name of the worker thread or process.
202 The incremental number of the worker thread or process.
205 The incremental number of the file for that worker thread or process.
208 To have dependent jobs share a set of files, this option can be set to
209 have fio generate filenames that are shared between the two. For instance,
210 if \fBtestfiles.$filenum\fR is specified, file number 4 for any job will
211 be named \fBtestfiles.4\fR. The default of \fB$jobname.$jobnum.$filenum\fR
212 will be used if no other format specifier is given.
216 .BI lockfile \fR=\fPstr
217 Fio defaults to not locking any files before it does IO to them. If a file or
218 file descriptor is shared, fio can serialize IO to that file to make the end
219 result consistent. This is usual for emulating real workloads that share files.
225 No locking. This is the default.
228 Only one thread or process may do IO at the time, excluding all others.
231 Read-write locking on the file. Many readers may access the file at the same
232 time, but writes get exclusive access.
236 .BI opendir \fR=\fPstr
237 Recursively open any files below directory \fIstr\fR.
239 .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr
240 Type of I/O pattern. Accepted values are:
251 Sequential trim (Linux block devices only).
260 Random trim (Linux block devices only).
263 Mixed sequential reads and writes.
266 Mixed random reads and writes.
269 For mixed I/O, the default split is 50/50. For certain types of io the result
270 may still be skewed a bit, since the speed may be different. It is possible to
271 specify a number of IO's to do before getting a new offset, this is done by
272 appending a `:\fI<nr>\fR to the end of the string given. For a random read, it
273 would look like \fBrw=randread:8\fR for passing in an offset modifier with a
274 value of 8. If the postfix is used with a sequential IO pattern, then the value
275 specified will be added to the generated offset for each IO. For instance,
276 using \fBrw=write:4k\fR will skip 4k for every write. It turns sequential IO
277 into sequential IO with holes. See the \fBrw_sequencer\fR option.
280 .BI rw_sequencer \fR=\fPstr
281 If an offset modifier is given by appending a number to the \fBrw=<str>\fR line,
282 then this option controls how that number modifies the IO offset being
283 generated. Accepted values are:
288 Generate sequential offset
291 Generate the same offset
294 \fBsequential\fR is only useful for random IO, where fio would normally
295 generate a new random offset for every IO. If you append eg 8 to randread, you
296 would get a new random offset for every 8 IO's. The result would be a seek for
297 only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify
298 that. As sequential IO is already sequential, setting \fBsequential\fR for that
299 would not result in any differences. \fBidentical\fR behaves in a similar
300 fashion, except it sends the same offset 8 number of times before generating a
305 .BI kb_base \fR=\fPint
306 The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage
307 manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious
308 reasons. Allowed values are 1024 or 1000, with 1024 being the default.
310 .BI unified_rw_reporting \fR=\fPbool
311 Fio normally reports statistics on a per data direction basis, meaning that
312 read, write, and trim are accounted and reported separately. If this option is
313 set, the fio will sum the results and report them as "mixed" instead.
315 .BI randrepeat \fR=\fPbool
316 Seed the random number generator used for random I/O patterns in a predictable
317 way so the pattern is repeatable across runs. Default: true.
319 .BI allrandrepeat \fR=\fPbool
320 Seed all random number generators in a predictable way so results are
321 repeatable across runs. Default: false.
323 .BI randseed \fR=\fPint
324 Seed the random number generators based on this seed value, to be able to
325 control what sequence of output is being generated. If not set, the random
326 sequence depends on the \fBrandrepeat\fR setting.
328 .BI use_os_rand \fR=\fPbool
329 Fio can either use the random generator supplied by the OS to generator random
330 offsets, or it can use it's own internal generator (based on Tausworthe).
331 Default is to use the internal generator, which is often of better quality and
332 faster. Default: false.
334 .BI fallocate \fR=\fPstr
335 Whether pre-allocation is performed when laying down files. Accepted values
341 Do not pre-allocate space.
344 Pre-allocate via \fBposix_fallocate\fR\|(3).
347 Pre-allocate via \fBfallocate\fR\|(2) with FALLOC_FL_KEEP_SIZE set.
350 Backward-compatible alias for 'none'.
353 Backward-compatible alias for 'posix'.
356 May not be available on all supported platforms. 'keep' is only
357 available on Linux. If using ZFS on Solaris this must be set to 'none'
358 because ZFS doesn't support it. Default: 'posix'.
361 .BI fadvise_hint \fR=\fPbool
362 Use of \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
363 are likely to be issued. Default: true.
366 Total size of I/O for this job. \fBfio\fR will run until this many bytes have
367 been transferred, unless limited by other options (\fBruntime\fR, for instance).
368 Unless \fBnrfiles\fR and \fBfilesize\fR options are given, this amount will be
369 divided between the available files for the job. If not set, fio will use the
370 full size of the given files or devices. If the files do not exist, size
371 must be given. It is also possible to give size as a percentage between 1 and
372 100. If size=20% is given, fio will use 20% of the full size of the given files
375 .BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool
376 Sets size to something really large and waits for ENOSPC (no space left on
377 device) as the terminating condition. Only makes sense with sequential write.
378 For a read workload, the mount point will be filled first then IO started on
379 the result. This option doesn't make sense if operating on a raw device node,
380 since the size of that is already known by the file system. Additionally,
381 writing beyond end-of-device will not return ENOSPC there.
383 .BI filesize \fR=\fPirange
384 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
385 for files at random within the given range, limited to \fBsize\fR in total (if
386 that is given). If \fBfilesize\fR is not specified, each created file is the
389 .BI file_append \fR=\fPbool
390 Perform IO after the end of the file. Normally fio will operate within the
391 size of a file. If this option is set, then fio will append to the file
392 instead. This has identical behavior to setting \fRoffset\fP to the size
393 of a file. This option is ignored on non-regular files.
395 .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
396 Block size for I/O units. Default: 4k. Values for reads, writes, and trims
397 can be specified separately in the format \fIread\fR,\fIwrite\fR,\fItrim\fR
398 either of which may be empty to leave that value at its default. If a trailing
399 comma isn't given, the remainder will inherit the last value set.
401 .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
402 Specify a range of I/O block sizes. The issued I/O unit will always be a
403 multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
404 to both reads and writes if only one range is given, but can be specified
405 separately with a comma separating the values. Example: bsrange=1k-4k,2k-8k.
406 Also (see \fBblocksize\fR).
408 .BI bssplit \fR=\fPstr
409 This option allows even finer grained control of the block sizes issued,
410 not just even splits between them. With this option, you can weight various
411 block sizes for exact control of the issued IO for a job that has mixed
412 block sizes. The format of the option is bssplit=blocksize/percentage,
413 optionally adding as many definitions as needed separated by a colon.
414 Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
415 blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
416 splits to reads and writes. The format is identical to what the
417 \fBbs\fR option accepts, the read and write parts are separated with a
420 .B blocksize_unaligned\fR,\fP bs_unaligned
421 If set, any size in \fBblocksize_range\fR may be used. This typically won't
422 work with direct I/O, as that normally requires sector alignment.
424 .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
425 At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
426 the minimum blocksize given. Minimum alignment is typically 512b
427 for using direct IO, though it usually depends on the hardware block size.
428 This option is mutually exclusive with using a random map for files, so it
429 will turn off that option.
431 .BI bs_is_seq_rand \fR=\fPbool
432 If this option is set, fio will use the normal read,write blocksize settings as
433 sequential,random instead. Any random read or write will use the WRITE
434 blocksize settings, and any sequential read or write will use the READ
438 Initialise buffers with all zeros. Default: fill buffers with random data.
439 The resulting IO buffers will not be completely zeroed, unless
440 \fPscramble_buffers\fR is also turned off.
443 If this option is given, fio will refill the IO buffers on every submit. The
444 default is to only fill it at init time and reuse that data. Only makes sense
445 if zero_buffers isn't specified, naturally. If data verification is enabled,
446 refill_buffers is also automatically enabled.
448 .BI scramble_buffers \fR=\fPbool
449 If \fBrefill_buffers\fR is too costly and the target is using data
450 deduplication, then setting this option will slightly modify the IO buffer
451 contents to defeat normal de-dupe attempts. This is not enough to defeat
452 more clever block compression attempts, but it will stop naive dedupe
453 of blocks. Default: true.
455 .BI buffer_compress_percentage \fR=\fPint
456 If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
457 that compress to the specified level. Fio does this by providing a mix of
458 random data and zeroes. Note that this is per block size unit, for file/disk
459 wide compression level that matches this setting, you'll also want to set
460 \fBrefill_buffers\fR.
462 .BI buffer_compress_chunk \fR=\fPint
463 See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how
464 big the ranges of random data and zeroed data is. Without this set, fio will
465 provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by
466 the remaining zeroed. With this set to some chunk size smaller than the block
467 size, fio can alternate random and zeroed data throughout the IO buffer.
469 .BI buffer_pattern \fR=\fPstr
470 If set, fio will fill the io buffers with this pattern. If not set, the contents
471 of io buffers is defined by the other options related to buffer contents. The
472 setting can be any pattern of bytes, and can be prefixed with 0x for hex
475 .BI nrfiles \fR=\fPint
476 Number of files to use for this job. Default: 1.
478 .BI openfiles \fR=\fPint
479 Number of files to keep open at the same time. Default: \fBnrfiles\fR.
481 .BI file_service_type \fR=\fPstr
482 Defines how files to service are selected. The following types are defined:
487 Choose a file at random.
490 Round robin over open files (default).
493 Do each file in the set sequentially.
496 The number of I/Os to issue before switching a new file can be specified by
497 appending `:\fIint\fR' to the service type.
500 .BI ioengine \fR=\fPstr
501 Defines how the job issues I/O. The following types are defined:
506 Basic \fBread\fR\|(2) or \fBwrite\fR\|(2) I/O. \fBfseek\fR\|(2) is used to
507 position the I/O location.
510 Basic \fBpread\fR\|(2) or \fBpwrite\fR\|(2) I/O.
513 Basic \fBreadv\fR\|(2) or \fBwritev\fR\|(2) I/O. Will emulate queuing by
514 coalescing adjacent IOs into a single submission.
517 Basic \fBpreadv\fR\|(2) or \fBpwritev\fR\|(2) I/O.
520 Linux native asynchronous I/O. This ioengine defines engine specific options.
523 POSIX asynchronous I/O using \fBaio_read\fR\|(3) and \fBaio_write\fR\|(3).
526 Solaris native asynchronous I/O.
529 Windows native asynchronous I/O.
532 File is memory mapped with \fBmmap\fR\|(2) and data copied using
536 \fBsplice\fR\|(2) is used to transfer the data and \fBvmsplice\fR\|(2) to
537 transfer data from user-space to the kernel.
540 Use the syslet system calls to make regular read/write asynchronous.
543 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
544 the target is an sg character device, we use \fBread\fR\|(2) and
545 \fBwrite\fR\|(2) for asynchronous I/O.
548 Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
549 itself and for debugging and testing purposes.
552 Transfer over the network. The protocol to be used can be defined with the
553 \fBprotocol\fR parameter. Depending on the protocol, \fBfilename\fR,
554 \fBhostname\fR, \fBport\fR, or \fBlisten\fR must be specified.
555 This ioengine defines engine specific options.
558 Like \fBnet\fR, but uses \fBsplice\fR\|(2) and \fBvmsplice\fR\|(2) to map data
559 and send/receive. This ioengine defines engine specific options.
562 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
563 \fBcpucycles\fR parameters.
566 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
567 approach to asynchronous I/O.
569 See <http://www.xmailserver.org/guasi\-lib.html>.
572 The RDMA I/O engine supports both RDMA memory semantics (RDMA_WRITE/RDMA_READ)
573 and channel semantics (Send/Recv) for the InfiniBand, RoCE and iWARP protocols.
576 Loads an external I/O engine object file. Append the engine filename as
580 IO engine that does regular linux native fallocate call to simulate data
581 transfer as fio ioengine
583 DDIR_READ does fallocate(,mode = FALLOC_FL_KEEP_SIZE,)
585 DIR_WRITE does fallocate(,mode = 0)
587 DDIR_TRIM does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE)
590 IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity
591 request to DDIR_WRITE event
594 IO engine supporting direct access to Ceph Rados Block Devices (RBD) via librbd
595 without the need to use the kernel rbd driver. This ioengine defines engine specific
601 .BI iodepth \fR=\fPint
602 Number of I/O units to keep in flight against the file. Note that increasing
603 iodepth beyond 1 will not affect synchronous ioengines (except for small
604 degress when verify_async is in use). Even async engines my impose OS
605 restrictions causing the desired depth not to be achieved. This may happen on
606 Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is
607 not async on that OS. Keep an eye on the IO depth distribution in the
608 fio output to verify that the achieved depth is as expected. Default: 1.
610 .BI iodepth_batch \fR=\fPint
611 Number of I/Os to submit at once. Default: \fBiodepth\fR.
613 .BI iodepth_batch_complete \fR=\fPint
614 This defines how many pieces of IO to retrieve at once. It defaults to 1 which
615 means that we'll ask for a minimum of 1 IO in the retrieval process from the
616 kernel. The IO retrieval will go on until we hit the limit set by
617 \fBiodepth_low\fR. If this variable is set to 0, then fio will always check for
618 completed events before queuing more IO. This helps reduce IO latency, at the
619 cost of more retrieval system calls.
621 .BI iodepth_low \fR=\fPint
622 Low watermark indicating when to start filling the queue again. Default:
625 .BI direct \fR=\fPbool
626 If true, use non-buffered I/O (usually O_DIRECT). Default: false.
628 .BI atomic \fR=\fPbool
629 If value is true, attempt to use atomic direct IO. Atomic writes are guaranteed
630 to be stable once acknowledged by the operating system. Only Linux supports
633 .BI buffered \fR=\fPbool
634 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
637 .BI offset \fR=\fPint
638 Offset in the file to start I/O. Data before the offset will not be touched.
640 .BI offset_increment \fR=\fPint
641 If this is provided, then the real offset becomes the
642 offset + offset_increment * thread_number, where the thread number is a counter
643 that starts at 0 and is incremented for each job. This option is useful if
644 there are several jobs which are intended to operate on a file in parallel in
645 disjoint segments, with even spacing between the starting points.
647 .BI number_ios \fR=\fPint
648 Fio will normally perform IOs until it has exhausted the size of the region
649 set by \fBsize\fR, or if it exhaust the allocated time (or hits an error
650 condition). With this setting, the range/size can be set independently of
651 the number of IOs to perform. When fio reaches this number, it will exit
652 normally and report status.
655 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
656 0, don't sync. Default: 0.
658 .BI fdatasync \fR=\fPint
659 Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the
660 data parts of the file. Default: 0.
662 .BI write_barrier \fR=\fPint
663 Make every Nth write a barrier write.
665 .BI sync_file_range \fR=\fPstr:int
666 Use \fBsync_file_range\fR\|(2) for every \fRval\fP number of write operations. Fio will
667 track range of writes that have happened since the last \fBsync_file_range\fR\|(2) call.
668 \fRstr\fP can currently be one or more of:
672 SYNC_FILE_RANGE_WAIT_BEFORE
675 SYNC_FILE_RANGE_WRITE
678 SYNC_FILE_RANGE_WRITE
682 So if you do sync_file_range=wait_before,write:8, fio would use
683 \fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes.
684 Also see the \fBsync_file_range\fR\|(2) man page. This option is Linux specific.
686 .BI overwrite \fR=\fPbool
687 If writing, setup the file first and do overwrites. Default: false.
689 .BI end_fsync \fR=\fPbool
690 Sync file contents when a write stage has completed. Default: false.
692 .BI fsync_on_close \fR=\fPbool
693 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
694 it will happen on every close, not just at the end of the job. Default: false.
696 .BI rwmixread \fR=\fPint
697 Percentage of a mixed workload that should be reads. Default: 50.
699 .BI rwmixwrite \fR=\fPint
700 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
701 \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two
702 overrides the first. This may interfere with a given rate setting, if fio is
703 asked to limit reads or writes to a certain rate. If that is the case, then
704 the distribution may be skewed. Default: 50.
706 .BI random_distribution \fR=\fPstr:float
707 By default, fio will use a completely uniform random distribution when asked
708 to perform random IO. Sometimes it is useful to skew the distribution in
709 specific ways, ensuring that some parts of the data is more hot than others.
710 Fio includes the following distribution models:
714 Uniform random distribution
724 When using a zipf or pareto distribution, an input value is also needed to
725 define the access pattern. For zipf, this is the zipf theta. For pareto,
726 it's the pareto power. Fio includes a test program, genzipf, that can be
727 used visualize what the given input values will yield in terms of hit rates.
728 If you wanted to use zipf with a theta of 1.2, you would use
729 random_distribution=zipf:1.2 as the option. If a non-uniform model is used,
730 fio will disable use of the random map.
732 .BI percentage_random \fR=\fPint
733 For a random workload, set how big a percentage should be random. This defaults
734 to 100%, in which case the workload is fully random. It can be set from
735 anywhere from 0 to 100. Setting it to 0 would make the workload fully
736 sequential. It is possible to set different values for reads, writes, and
737 trim. To do so, simply use a comma separated list. See \fBblocksize\fR.
740 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
741 this parameter is given, a new offset will be chosen without looking at past
742 I/O history. This parameter is mutually exclusive with \fBverify\fR.
744 .BI softrandommap \fR=\fPbool
745 See \fBnorandommap\fR. If fio runs with the random block map enabled and it
746 fails to allocate the map, if this option is set it will continue without a
747 random block map. As coverage will not be as complete as with random maps, this
748 option is disabled by default.
750 .BI random_generator \fR=\fPstr
751 Fio supports the following engines for generating IO offsets for random IO:
755 Strong 2^88 cycle random number generator
758 Linear feedback shift register generator
762 Tausworthe is a strong random number generator, but it requires tracking on the
763 side if we want to ensure that blocks are only read or written once. LFSR
764 guarantees that we never generate the same offset twice, and it's also less
765 computationally expensive. It's not a true random generator, however, though
766 for IO purposes it's typically good enough. LFSR only works with single block
767 sizes, not with workloads that use multiple block sizes. If used with such a
768 workload, fio may read or write some blocks multiple times.
771 Run job with given nice value. See \fBnice\fR\|(2).
774 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
777 .BI prioclass \fR=\fPint
778 Set I/O priority class. See \fBionice\fR\|(1).
780 .BI thinktime \fR=\fPint
781 Stall job for given number of microseconds between issuing I/Os.
783 .BI thinktime_spin \fR=\fPint
784 Pretend to spend CPU time for given number of microseconds, sleeping the rest
785 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
787 .BI thinktime_blocks \fR=\fPint
788 Only valid if thinktime is set - control how many blocks to issue, before
789 waiting \fBthinktime\fR microseconds. If not set, defaults to 1 which will
790 make fio wait \fBthinktime\fR microseconds after every block. This
791 effectively makes any queue depth setting redundant, since no more than 1 IO
792 will be queued before we have to complete it and do our thinktime. In other
793 words, this setting effectively caps the queue depth if the latter is larger.
797 Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix
798 rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each,
799 or you can specify read and writes separately. Using \fBrate\fR=1m,500k would
800 limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes
801 can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only
802 limit writes (to 500KB/sec), the latter will only limit reads.
804 .BI ratemin \fR=\fPint
805 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
806 Failing to meet this requirement will cause the job to exit. The same format
807 as \fBrate\fR is used for read vs write separation.
809 .BI rate_iops \fR=\fPint
810 Cap the bandwidth to this number of IOPS. Basically the same as rate, just
811 specified independently of bandwidth. The same format as \fBrate\fR is used for
812 read vs write separation. If \fBblocksize\fR is a range, the smallest block
813 size is used as the metric.
815 .BI rate_iops_min \fR=\fPint
816 If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR
817 is used for read vs write separation.
819 .BI ratecycle \fR=\fPint
820 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
821 milliseconds. Default: 1000ms.
823 .BI latency_target \fR=\fPint
824 If set, fio will attempt to find the max performance point that the given
825 workload will run at while maintaining a latency below this target. The
826 values is given in microseconds. See \fBlatency_window\fR and
827 \fBlatency_percentile\fR.
829 .BI latency_window \fR=\fPint
830 Used with \fBlatency_target\fR to specify the sample window that the job
831 is run at varying queue depths to test the performance. The value is given
834 .BI latency_percentile \fR=\fPfloat
835 The percentage of IOs that must fall within the criteria specified by
836 \fBlatency_target\fR and \fBlatency_window\fR. If not set, this defaults
837 to 100.0, meaning that all IOs must be equal or below to the value set
838 by \fBlatency_target\fR.
840 .BI max_latency \fR=\fPint
841 If set, fio will exit the job if it exceeds this maximum latency. It will exit
844 .BI cpumask \fR=\fPint
845 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
846 may run on. See \fBsched_setaffinity\fR\|(2).
848 .BI cpus_allowed \fR=\fPstr
849 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
851 .BI cpus_allowed_policy \fR=\fPstr
852 Set the policy of how fio distributes the CPUs specified by \fBcpus_allowed\fR
853 or \fBcpumask\fR. Two policies are supported:
858 All jobs will share the CPU set specified.
861 Each job will get a unique CPU from the CPU set.
864 \fBshared\fR is the default behaviour, if the option isn't specified. If
865 \fBsplit\fR is specified, then fio will assign one cpu per job. If not enough
866 CPUs are given for the jobs listed, then fio will roundrobin the CPUs in
871 .BI numa_cpu_nodes \fR=\fPstr
872 Set this job running on specified NUMA nodes' CPUs. The arguments allow
873 comma delimited list of cpu numbers, A-B ranges, or 'all'.
875 .BI numa_mem_policy \fR=\fPstr
876 Set this job's memory policy and corresponding NUMA nodes. Format of
880 .B <mode>[:<nodelist>]
883 is one of the following memory policy:
885 .B default, prefer, bind, interleave, local
888 For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is
889 needed to be specified. For \fBprefer\fR, only one node is
890 allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows
891 comma delimited list of numbers, A-B ranges, or 'all'.
893 .BI startdelay \fR=\fPirange
894 Delay start of job for the specified number of seconds. Supports all time
895 suffixes to allow specification of hours, minutes, seconds and
896 milliseconds - seconds are the default if a unit is ommited.
897 Can be given as a range which causes each thread to choose randomly out of the
900 .BI runtime \fR=\fPint
901 Terminate processing after the specified number of seconds.
904 If given, run for the specified \fBruntime\fR duration even if the files are
905 completely read or written. The same workload will be repeated as many times
906 as \fBruntime\fR allows.
908 .BI ramp_time \fR=\fPint
909 If set, fio will run the specified workload for this amount of time before
910 logging any performance numbers. Useful for letting performance settle before
911 logging results, thus minimizing the runtime required for stable results. Note
912 that the \fBramp_time\fR is considered lead in time for a job, thus it will
913 increase the total runtime if a special timeout or runtime is specified.
915 .BI invalidate \fR=\fPbool
916 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
919 Use synchronous I/O for buffered writes. For the majority of I/O engines,
920 this means using O_SYNC. Default: false.
922 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
923 Allocation method for I/O unit buffer. Allowed values are:
928 Allocate memory with \fBmalloc\fR\|(3).
931 Use shared memory buffers allocated through \fBshmget\fR\|(2).
934 Same as \fBshm\fR, but use huge pages as backing.
937 Use \fBmmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
938 is given after the option in the format `:\fIfile\fR'.
941 Same as \fBmmap\fR, but use huge files as backing.
944 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
945 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
946 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
947 have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux,
948 huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR
949 and the documentation for that. Normally you just need to echo an appropriate
950 number, eg echoing 8 will ensure that the OS has 8 huge pages ready for
954 .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint
955 This indicates the memory alignment of the IO memory buffers. Note that the
956 given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR
957 the alignment of the following buffers are given by the \fBbs\fR used. In
958 other words, if using a \fBbs\fR that is a multiple of the page sized in the
959 system, all buffers will be aligned to this value. If using a \fBbs\fR that
960 is not page aligned, the alignment of subsequent IO memory buffers is the
961 sum of the \fBiomem_align\fR and \fBbs\fR used.
963 .BI hugepage\-size \fR=\fPint
964 Defines the size of a huge page. Must be at least equal to the system setting.
965 Should be a multiple of 1MB. Default: 4MB.
968 Terminate all jobs when one finishes. Default: wait for each job to finish.
970 .BI bwavgtime \fR=\fPint
971 Average bandwidth calculations over the given time in milliseconds. Default:
974 .BI iopsavgtime \fR=\fPint
975 Average IOPS calculations over the given time in milliseconds. Default:
978 .BI create_serialize \fR=\fPbool
979 If true, serialize file creation for the jobs. Default: true.
981 .BI create_fsync \fR=\fPbool
982 \fBfsync\fR\|(2) data file after creation. Default: true.
984 .BI create_on_open \fR=\fPbool
985 If true, the files are not created until they are opened for IO by the job.
987 .BI create_only \fR=\fPbool
988 If true, fio will only run the setup phase of the job. If files need to be
989 laid out or updated on disk, only that will be done. The actual job contents
992 .BI pre_read \fR=\fPbool
993 If this is given, files will be pre-read into memory before starting the given
994 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
995 pointless to pre-read and then drop the cache. This will only work for IO
996 engines that are seekable, since they allow you to read the same data
997 multiple times. Thus it will not work on eg network or splice IO.
999 .BI unlink \fR=\fPbool
1000 Unlink job files when done. Default: false.
1002 .BI loops \fR=\fPint
1003 Specifies the number of iterations (runs of the same workload) of this job.
1006 .BI verify_only \fR=\fPbool
1007 Do not perform the specified workload, only verify data still matches previous
1008 invocation of this workload. This option allows one to check data multiple
1009 times at a later date without overwriting it. This option makes sense only for
1010 workloads that write data, and does not support workloads with the
1011 \fBtime_based\fR option set.
1013 .BI do_verify \fR=\fPbool
1014 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
1017 .BI verify \fR=\fPstr
1018 Method of verifying file contents after each iteration of the job. Allowed
1023 .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1 xxhash
1024 Store appropriate checksum in the header of each block. crc32c-intel is
1025 hardware accelerated SSE4.2 driven, falls back to regular crc32c if
1026 not supported by the system.
1029 Write extra information about each I/O (timestamp, block number, etc.). The
1030 block number is verified. See \fBverify_pattern\fR as well.
1033 Pretend to verify. Used for testing internals.
1036 This option can be used for repeated burn-in tests of a system to make sure
1037 that the written data is also correctly read back. If the data direction given
1038 is a read or random read, fio will assume that it should verify a previously
1039 written file. If the data direction includes any form of write, the verify will
1040 be of the newly written data.
1043 .BI verifysort \fR=\fPbool
1044 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
1045 read them back in a sorted manner. Default: true.
1047 .BI verifysort_nr \fR=\fPint
1048 Pre-load and sort verify blocks for a read workload.
1050 .BI verify_offset \fR=\fPint
1051 Swap the verification header with data somewhere else in the block before
1052 writing. It is swapped back before verifying.
1054 .BI verify_interval \fR=\fPint
1055 Write the verification header for this number of bytes, which should divide
1056 \fBblocksize\fR. Default: \fBblocksize\fR.
1058 .BI verify_pattern \fR=\fPstr
1059 If set, fio will fill the io buffers with this pattern. Fio defaults to filling
1060 with totally random bytes, but sometimes it's interesting to fill with a known
1061 pattern for io verification purposes. Depending on the width of the pattern,
1062 fio will fill 1/2/3/4 bytes of the buffer at the time(it can be either a
1063 decimal or a hex number). The verify_pattern if larger than a 32-bit quantity
1064 has to be a hex number that starts with either "0x" or "0X". Use with
1067 .BI verify_fatal \fR=\fPbool
1068 If true, exit the job on the first observed verification failure. Default:
1071 .BI verify_dump \fR=\fPbool
1072 If set, dump the contents of both the original data block and the data block we
1073 read off disk to files. This allows later analysis to inspect just what kind of
1074 data corruption occurred. Off by default.
1076 .BI verify_async \fR=\fPint
1077 Fio will normally verify IO inline from the submitting thread. This option
1078 takes an integer describing how many async offload threads to create for IO
1079 verification instead, causing fio to offload the duty of verifying IO contents
1080 to one or more separate threads. If using this offload option, even sync IO
1081 engines can benefit from using an \fBiodepth\fR setting higher than 1, as it
1082 allows them to have IO in flight while verifies are running.
1084 .BI verify_async_cpus \fR=\fPstr
1085 Tell fio to set the given CPU affinity on the async IO verification threads.
1086 See \fBcpus_allowed\fP for the format used.
1088 .BI verify_backlog \fR=\fPint
1089 Fio will normally verify the written contents of a job that utilizes verify
1090 once that job has completed. In other words, everything is written then
1091 everything is read back and verified. You may want to verify continually
1092 instead for a variety of reasons. Fio stores the meta data associated with an
1093 IO block in memory, so for large verify workloads, quite a bit of memory would
1094 be used up holding this meta data. If this option is enabled, fio will write
1095 only N blocks before verifying these blocks.
1097 .BI verify_backlog_batch \fR=\fPint
1098 Control how many blocks fio will verify if verify_backlog is set. If not set,
1099 will default to the value of \fBverify_backlog\fR (meaning the entire queue is
1100 read back and verified). If \fBverify_backlog_batch\fR is less than
1101 \fBverify_backlog\fR then not all blocks will be verified, if
1102 \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks
1103 will be verified more than once.
1105 .BI trim_percentage \fR=\fPint
1106 Number of verify blocks to discard/trim.
1108 .BI trim_verify_zero \fR=\fPbool
1109 Verify that trim/discarded blocks are returned as zeroes.
1111 .BI trim_backlog \fR=\fPint
1112 Trim after this number of blocks are written.
1114 .BI trim_backlog_batch \fR=\fPint
1115 Trim this number of IO blocks.
1117 .BI experimental_verify \fR=\fPbool
1118 Enable experimental verification.
1120 .B stonewall "\fR,\fP wait_for_previous"
1121 Wait for preceding jobs in the job file to exit before starting this one.
1122 \fBstonewall\fR implies \fBnew_group\fR.
1125 Start a new reporting group. If not given, all jobs in a file will be part
1126 of the same reporting group, unless separated by a stonewall.
1128 .BI numjobs \fR=\fPint
1129 Number of clones (processes/threads performing the same workload) of this job.
1133 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
1137 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
1138 with \fBfork\fR\|(2).
1140 .BI zonesize \fR=\fPint
1141 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
1143 .BI zonerange \fR=\fPint
1144 Give size of an IO zone. See \fBzoneskip\fR.
1146 .BI zoneskip \fR=\fPint
1147 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
1150 .BI write_iolog \fR=\fPstr
1151 Write the issued I/O patterns to the specified file. Specify a separate file
1152 for each job, otherwise the iologs will be interspersed and the file may be
1155 .BI read_iolog \fR=\fPstr
1156 Replay the I/O patterns contained in the specified file generated by
1157 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
1159 .BI replay_no_stall \fR=\fPint
1160 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1161 attempts to respect timing information between I/Os. Enabling
1162 \fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
1163 still respecting ordering.
1165 .BI replay_redirect \fR=\fPstr
1166 While replaying I/O patterns using \fBread_iolog\fR the default behavior
1167 is to replay the IOPS onto the major/minor device that each IOP was recorded
1168 from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
1169 single specified device regardless of the device it was recorded from.
1171 .BI write_bw_log \fR=\fPstr
1172 If given, write a bandwidth log of the jobs in this job file. Can be used to
1173 store data of the bandwidth of the jobs in their lifetime. The included
1174 fio_generate_plots script uses gnuplot to turn these text files into nice
1175 graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
1176 option, the postfix is _bw.log.
1178 .BI write_lat_log \fR=\fPstr
1179 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
1180 filename is given with this option, the default filename of "jobname_type.log"
1181 is used. Even if the filename is given, fio will still append the type of log.
1183 .BI write_iops_log \fR=\fPstr
1184 Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
1185 option, the default filename of "jobname_type.log" is used. Even if the
1186 filename is given, fio will still append the type of log.
1188 .BI log_avg_msec \fR=\fPint
1189 By default, fio will log an entry in the iops, latency, or bw log for every
1190 IO that completes. When writing to the disk log, that can quickly grow to a
1191 very large size. Setting this option makes fio average the each log entry
1192 over the specified period of time, reducing the resolution of the log.
1195 .BI disable_lat \fR=\fPbool
1196 Disable measurements of total latency numbers. Useful only for cutting
1197 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
1198 really high IOPS rates. Note that to really get rid of a large amount of these
1199 calls, this option must be used with disable_slat and disable_bw as well.
1201 .BI disable_clat \fR=\fPbool
1202 Disable measurements of completion latency numbers. See \fBdisable_lat\fR.
1204 .BI disable_slat \fR=\fPbool
1205 Disable measurements of submission latency numbers. See \fBdisable_lat\fR.
1207 .BI disable_bw_measurement \fR=\fPbool
1208 Disable measurements of throughput/bandwidth numbers. See \fBdisable_lat\fR.
1210 .BI lockmem \fR=\fPint
1211 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
1212 simulate a smaller amount of memory. The amount specified is per worker.
1214 .BI exec_prerun \fR=\fPstr
1215 Before running the job, execute the specified command with \fBsystem\fR\|(3).
1217 Output is redirected in a file called \fBjobname.prerun.txt\fR
1220 .BI exec_postrun \fR=\fPstr
1221 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
1223 Output is redirected in a file called \fBjobname.postrun.txt\fR
1226 .BI ioscheduler \fR=\fPstr
1227 Attempt to switch the device hosting the file to the specified I/O scheduler.
1229 .BI disk_util \fR=\fPbool
1230 Generate disk utilization statistics if the platform supports it. Default: true.
1232 .BI clocksource \fR=\fPstr
1233 Use the given clocksource as the base of timing. The supported options are:
1237 \fBgettimeofday\fR\|(2)
1240 \fBclock_gettime\fR\|(2)
1243 Internal CPU clock source
1247 \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast
1248 (and fio is heavy on time calls). Fio will automatically use this clocksource
1249 if it's supported and considered reliable on the system it is running on,
1250 unless another clocksource is specifically set. For x86/x86-64 CPUs, this
1251 means supporting TSC Invariant.
1253 .BI gtod_reduce \fR=\fPbool
1254 Enable all of the \fBgettimeofday\fR\|(2) reducing options (disable_clat, disable_slat,
1255 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
1256 \fBgettimeofday\fR\|(2) call count. With this option enabled, we only do about 0.4% of
1257 the gtod() calls we would have done if all time keeping was enabled.
1259 .BI gtod_cpu \fR=\fPint
1260 Sometimes it's cheaper to dedicate a single thread of execution to just getting
1261 the current time. Fio (and databases, for instance) are very intensive on
1262 \fBgettimeofday\fR\|(2) calls. With this option, you can set one CPU aside for doing
1263 nothing but logging current time to a shared memory location. Then the other
1264 threads/processes that run IO workloads need only copy that segment, instead of
1265 entering the kernel with a \fBgettimeofday\fR\|(2) call. The CPU set aside for doing
1266 these time calls will be excluded from other uses. Fio will manually clear it
1267 from the CPU mask of other jobs.
1269 .BI ignore_error \fR=\fPstr
1270 Sometimes you want to ignore some errors during test in that case you can specify
1271 error list for each error type.
1273 ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST
1275 errors for given error type is separated with ':'.
1276 Error may be symbol ('ENOSPC', 'ENOMEM') or an integer.
1278 Example: ignore_error=EAGAIN,ENOSPC:122 .
1280 This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE.
1282 .BI error_dump \fR=\fPbool
1283 If set dump every error even if it is non fatal, true by default. If disabled
1284 only fatal error will be dumped
1286 .BI profile \fR=\fPstr
1287 Select a specific builtin performance test.
1289 .BI cgroup \fR=\fPstr
1290 Add job to this control group. If it doesn't exist, it will be created.
1291 The system must have a mounted cgroup blkio mount point for this to work. If
1292 your system doesn't have it mounted, you can do so with:
1294 # mount \-t cgroup \-o blkio none /cgroup
1296 .BI cgroup_weight \fR=\fPint
1297 Set the weight of the cgroup to this value. See the documentation that comes
1298 with the kernel, allowed values are in the range of 100..1000.
1300 .BI cgroup_nodelete \fR=\fPbool
1301 Normally fio will delete the cgroups it has created after the job completion.
1302 To override this behavior and to leave cgroups around after the job completion,
1303 set cgroup_nodelete=1. This can be useful if one wants to inspect various
1304 cgroup files after job completion. Default: false
1307 Instead of running as the invoking user, set the user ID to this value before
1308 the thread/process does any work.
1311 Set group ID, see \fBuid\fR.
1313 .BI unit_base \fR=\fPint
1314 Base unit for reporting. Allowed values are:
1318 Use auto-detection (default).
1328 .BI flow_id \fR=\fPint
1329 The ID of the flow. If not specified, it defaults to being a global flow. See
1333 Weight in token-based flow control. If this value is used, then there is a
1334 \fBflow counter\fR which is used to regulate the proportion of activity between
1335 two or more jobs. fio attempts to keep this flow counter near zero. The
1336 \fBflow\fR parameter stands for how much should be added or subtracted to the
1337 flow counter on each iteration of the main I/O loop. That is, if one job has
1338 \fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly
1339 1:8 ratio in how much one runs vs the other.
1341 .BI flow_watermark \fR=\fPint
1342 The maximum value that the absolute value of the flow counter is allowed to
1343 reach before the job must wait for a lower value of the counter.
1345 .BI flow_sleep \fR=\fPint
1346 The period of time, in microseconds, to wait after the flow watermark has been
1347 exceeded before retrying operations
1349 .BI clat_percentiles \fR=\fPbool
1350 Enable the reporting of percentiles of completion latencies.
1352 .BI percentile_list \fR=\fPfloat_list
1353 Overwrite the default list of percentiles for completion
1354 latencies. Each number is a floating number in the range (0,100], and
1355 the maximum length of the list is 20. Use ':' to separate the
1356 numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
1357 report the values of completion latency below which 99.5% and 99.9% of
1358 the observed latencies fell, respectively.
1359 .SS "Ioengine Parameters List"
1360 Some parameters are only valid when a specific ioengine is in use. These are
1361 used identically to normal parameters, with the caveat that when used on the
1362 command line, the must come after the ioengine that defines them is selected.
1364 .BI (cpu)cpuload \fR=\fPint
1365 Attempt to use the specified percentage of CPU cycles.
1367 .BI (cpu)cpuchunks \fR=\fPint
1368 Split the load into cycles of the given time. In microseconds.
1370 .BI (cpu)exit_on_io_done \fR=\fPbool
1371 Detect when IO threads are done, then exit.
1373 .BI (libaio)userspace_reap
1374 Normally, with the libaio engine in use, fio will use
1375 the io_getevents system call to reap newly returned events.
1376 With this flag turned on, the AIO ring will be read directly
1377 from user-space to reap events. The reaping mode is only
1378 enabled when polling for a minimum of 0 events (eg when
1379 iodepth_batch_complete=0).
1381 .BI (net,netsplice)hostname \fR=\fPstr
1382 The host name or IP address to use for TCP or UDP based IO.
1383 If the job is a TCP listener or UDP reader, the hostname is not
1384 used and must be omitted unless it is a valid UDP multicast address.
1386 .BI (net,netsplice)port \fR=\fPint
1387 The TCP or UDP port to bind to or connect to.
1389 .BI (net,netsplice)interface \fR=\fPstr
1390 The IP address of the network interface used to send or receive UDP multicast
1393 .BI (net,netsplice)ttl \fR=\fPint
1394 Time-to-live value for outgoing UDP multicast packets. Default: 1
1396 .BI (net,netsplice)nodelay \fR=\fPbool
1397 Set TCP_NODELAY on TCP connections.
1399 .BI (net,netsplice)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr
1400 The network protocol to use. Accepted values are:
1405 Transmission control protocol
1408 Transmission control protocol V6
1411 User datagram protocol
1414 User datagram protocol V6
1420 When the protocol is TCP or UDP, the port must also be given,
1421 as well as the hostname if the job is a TCP listener or UDP
1422 reader. For unix sockets, the normal filename option should be
1423 used and the port is invalid.
1426 .BI (net,netsplice)listen
1427 For TCP network connections, tell fio to listen for incoming
1428 connections rather than initiating an outgoing connection. The
1429 hostname must be omitted if this option is used.
1431 .BI (net, pingpong) \fR=\fPbool
1432 Normally a network writer will just continue writing data, and a network reader
1433 will just consume packages. If pingpong=1 is set, a writer will send its normal
1434 payload to the reader, then wait for the reader to send the same payload back.
1435 This allows fio to measure network latencies. The submission and completion
1436 latencies then measure local time spent sending or receiving, and the
1437 completion latency measures how long it took for the other end to receive and
1438 send back. For UDP multicast traffic pingpong=1 should only be set for a single
1439 reader when multiple readers are listening to the same address.
1441 .BI (e4defrag,donorname) \fR=\fPstr
1442 File will be used as a block donor (swap extents between files)
1444 .BI (e4defrag,inplace) \fR=\fPint
1445 Configure donor file block allocation strategy
1448 Preallocate donor's file on init
1451 allocate space immediately inside defragment event, and free right after event
1454 .BI (rbd)rbdname \fR=\fPstr
1455 Specifies the name of the RBD.
1457 .BI (rbd)pool \fR=\fPstr
1458 Specifies the name of the Ceph pool containing the RBD.
1460 .BI (rbd)clientname \fR=\fPstr
1461 Specifies the username (without the 'client.' prefix) used to access the Ceph cluster.
1463 While running, \fBfio\fR will display the status of the created jobs. For
1467 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
1470 The characters in the first set of brackets denote the current status of each
1471 threads. The possible values are:
1477 Setup but not started.
1483 Initialized, waiting.
1486 Running, doing sequential reads.
1489 Running, doing random reads.
1492 Running, doing sequential writes.
1495 Running, doing random writes.
1498 Running, doing mixed sequential reads/writes.
1501 Running, doing mixed random reads/writes.
1504 Running, currently waiting for \fBfsync\fR\|(2).
1507 Running, verifying written data.
1510 Exited, not reaped by main thread.
1513 Exited, thread reaped.
1517 The second set of brackets shows the estimated completion percentage of
1518 the current group. The third set shows the read and write I/O rate,
1519 respectively. Finally, the estimated run time of the job is displayed.
1521 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
1522 for each thread, each group of threads, and each disk, in that order.
1524 Per-thread statistics first show the threads client number, group-id, and
1525 error code. The remaining figures are as follows:
1529 Number of megabytes of I/O performed.
1532 Average data rate (bandwidth).
1538 Submission latency minimum, maximum, average and standard deviation. This is
1539 the time it took to submit the I/O.
1542 Completion latency minimum, maximum, average and standard deviation. This
1543 is the time between submission and completion.
1546 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
1547 and standard deviation.
1550 CPU usage statistics. Includes user and system time, number of context switches
1551 this thread went through and number of major and minor page faults.
1554 Distribution of I/O depths. Each depth includes everything less than (or equal)
1555 to it, but greater than the previous depth.
1558 Number of read/write requests issued, and number of short read/write requests.
1561 Distribution of I/O completion latencies. The numbers follow the same pattern
1565 The group statistics show:
1570 Number of megabytes I/O performed.
1573 Aggregate bandwidth of threads in the group.
1576 Minimum average bandwidth a thread saw.
1579 Maximum average bandwidth a thread saw.
1582 Shortest runtime of threads in the group.
1585 Longest runtime of threads in the group.
1589 Finally, disk statistics are printed with reads first:
1594 Number of I/Os performed by all groups.
1597 Number of merges in the I/O scheduler.
1600 Number of ticks we kept the disk busy.
1603 Total time spent in the disk queue.
1610 It is also possible to get fio to dump the current output while it is
1611 running, without terminating the job. To do that, send fio the \fBUSR1\fR
1614 If the \fB\-\-minimal\fR / \fB\-\-append-terse\fR options are given, the
1615 results will be printed/appended in a semicolon-delimited format suitable for
1617 A job description (if provided) follows on a new line. Note that the first
1618 number in the line is the version number. If the output has to be changed
1619 for some reason, this number will be incremented by 1 to signify that
1620 change. The fields are:
1623 .B terse version, fio version, jobname, groupid, error
1627 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1631 .B min, max, mean, standard deviation
1635 .B min, max, mean, standard deviation
1637 Completion latency percentiles (20 fields):
1639 .B Xth percentile=usec
1643 .B min, max, mean, standard deviation
1647 .B min, max, aggregate percentage of total, mean, standard deviation
1653 .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP
1657 .B min, max, mean, standard deviation
1661 .B min, max, mean, standard deviation
1663 Completion latency percentiles (20 fields):
1665 .B Xth percentile=usec
1669 .B min, max, mean, standard deviation
1673 .B min, max, aggregate percentage of total, mean, standard deviation
1679 .B user, system, context switches, major page faults, minor page faults
1682 IO depth distribution:
1684 .B <=1, 2, 4, 8, 16, 32, >=64
1687 IO latency distribution:
1691 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
1695 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
1699 Disk utilization (1 for each disk used):
1701 .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
1704 Error Info (dependent on continue_on_error, default off):
1706 .B total # errors, first error code
1709 .B text description (if provided in config - appears on newline)
1712 Normally you would run fio as a stand-alone application on the machine
1713 where the IO workload should be generated. However, it is also possible to
1714 run the frontend and backend of fio separately. This makes it possible to
1715 have a fio server running on the machine(s) where the IO workload should
1716 be running, while controlling it from another machine.
1718 To start the server, you would do:
1720 \fBfio \-\-server=args\fR
1722 on that machine, where args defines what fio listens to. The arguments
1723 are of the form 'type:hostname or IP:port'. 'type' is either 'ip' (or ip4)
1724 for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain
1725 socket. 'hostname' is either a hostname or IP address, and 'port' is the port to
1726 listen to (only valid for TCP/IP, not a local socket). Some examples:
1730 Start a fio server, listening on all interfaces on the default port (8765).
1732 2) fio \-\-server=ip:hostname,4444
1734 Start a fio server, listening on IP belonging to hostname and on port 4444.
1736 3) fio \-\-server=ip6:::1,4444
1738 Start a fio server, listening on IPv6 localhost ::1 and on port 4444.
1740 4) fio \-\-server=,4444
1742 Start a fio server, listening on all interfaces on port 4444.
1744 5) fio \-\-server=1.2.3.4
1746 Start a fio server, listening on IP 1.2.3.4 on the default port.
1748 6) fio \-\-server=sock:/tmp/fio.sock
1750 Start a fio server, listening on the local socket /tmp/fio.sock.
1752 When a server is running, you can connect to it from a client. The client
1755 fio \-\-local-args \-\-client=server \-\-remote-args <job file(s)>
1757 where \-\-local-args are arguments that are local to the client where it is
1758 running, 'server' is the connect string, and \-\-remote-args and <job file(s)>
1759 are sent to the server. The 'server' string follows the same format as it
1760 does on the server side, to allow IP/hostname/socket and port strings.
1761 You can connect to multiple clients as well, to do that you could run:
1763 fio \-\-client=server2 \-\-client=server2 <job file(s)>
1767 was written by Jens Axboe <jens.axboe@oracle.com>,
1768 now Jens Axboe <jaxboe@fusionio.com>.
1770 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
1771 on documentation by Jens Axboe.
1772 .SH "REPORTING BUGS"
1773 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
1776 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
1778 Sample jobfiles are available in the \fBexamples\fR directory.
projects / fio.git / blob