| .TH fio 1 "September 2007" "User Manual" |
| .SH NAME |
| fio \- flexible I/O tester |
| .SH SYNOPSIS |
| .B fio |
| [\fIoptions\fR] [\fIjobfile\fR]... |
| .SH DESCRIPTION |
| .B fio |
| is a tool that will spawn a number of threads or processes doing a |
| particular type of I/O action as specified by the user. |
| The typical use of fio is to write a job file matching the I/O load |
| one wants to simulate. |
| .SH OPTIONS |
| .TP |
| .BI \-\-debug \fR=\fPtype |
| Enable verbose tracing of various fio actions. May be `all' for all types |
| or individual types separated by a comma (eg \-\-debug=io,file). `help' will |
| list all available tracing options. |
| .TP |
| .BI \-\-output \fR=\fPfilename |
| Write output to \fIfilename\fR. |
| .TP |
| .BI \-\-runtime \fR=\fPruntime |
| Limit run time to \fIruntime\fR seconds. |
| .TP |
| .B \-\-latency\-log |
| Generate per-job latency logs. |
| .TP |
| .B \-\-bandwidth\-log |
| Generate per-job bandwidth logs. |
| .TP |
| .B \-\-minimal |
| Print statistics in a terse, semicolon-delimited format. |
| .TP |
| .B \-\-version |
| Display version information and exit. |
| .TP |
| .BI \-\-terse\-version \fR=\fPversion |
| Set terse version output format (Current version 3, or older version 2). |
| .TP |
| .B \-\-help |
| Display usage information and exit. |
| .TP |
| .BI \-\-cmdhelp \fR=\fPcommand |
| Print help information for \fIcommand\fR. May be `all' for all commands. |
| .TP |
| .BI \-\-enghelp \fR=\fPioengine[,command] |
| List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR defined by \fIioengine\fR. |
| .TP |
| .BI \-\-showcmd \fR=\fPjobfile |
| Convert \fIjobfile\fR to a set of command-line options. |
| .TP |
| .BI \-\-eta \fR=\fPwhen |
| Specifies when real-time ETA estimate should be printed. \fIwhen\fR may |
| be one of `always', `never' or `auto'. |
| .TP |
| .BI \-\-eta\-newline \fR=\fPtime |
| Force an ETA newline for every `time` period passed. |
| .TP |
| .BI \-\-status\-interval \fR=\fPtime |
| Report full output status every `time` period passed. |
| .TP |
| .BI \-\-readonly |
| Turn on safety read-only checks, preventing any attempted write. |
| .TP |
| .BI \-\-section \fR=\fPsec |
| Only run section \fIsec\fR from job file. Multiple of these options can be given, adding more sections to run. |
| .TP |
| .BI \-\-alloc\-size \fR=\fPkb |
| Set the internal smalloc pool size to \fIkb\fP kilobytes. |
| .TP |
| .BI \-\-warnings\-fatal |
| All fio parser warnings are fatal, causing fio to exit with an error. |
| .TP |
| .BI \-\-max\-jobs \fR=\fPnr |
| Set the maximum allowed number of jobs (threads/processes) to support. |
| .TP |
| .BI \-\-server \fR=\fPargs |
| Start a backend server, with \fIargs\fP specifying what to listen to. See client/server section. |
| .TP |
| .BI \-\-daemonize \fR=\fPpidfile |
| Background a fio server, writing the pid to the given pid file. |
| .TP |
| .BI \-\-client \fR=\fPhost |
| Instead of running the jobs locally, send and run them on the given host. |
| .TP |
| .BI \-\-idle\-prof \fR=\fPoption |
| Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate). |
| .SH "JOB FILE FORMAT" |
| Job files are in `ini' format. They consist of one or more |
| job definitions, which begin with a job name in square brackets and |
| extend to the next job name. The job name can be any ASCII string |
| except `global', which has a special meaning. Following the job name is |
| a sequence of zero or more parameters, one per line, that define the |
| behavior of the job. Any line starting with a `;' or `#' character is |
| considered a comment and ignored. |
| .P |
| If \fIjobfile\fR is specified as `-', the job file will be read from |
| standard input. |
| .SS "Global Section" |
| The global section contains default parameters for jobs specified in the |
| job file. A job is only affected by global sections residing above it, |
| and there may be any number of global sections. Specific job definitions |
| may override any parameter set in global sections. |
| .SH "JOB PARAMETERS" |
| .SS Types |
| Some parameters may take arguments of a specific type. The types used are: |
| .TP |
| .I str |
| String: a sequence of alphanumeric characters. |
| .TP |
| .I int |
| SI integer: a whole number, possibly containing a suffix denoting the base unit |
| of the value. Accepted suffixes are `k', 'M', 'G', 'T', and 'P', denoting |
| kilo (1024), mega (1024^2), giga (1024^3), tera (1024^4), and peta (1024^5) |
| respectively. The suffix is not case sensitive. If prefixed with '0x', the |
| value is assumed to be base 16 (hexadecimal). A suffix may include a trailing 'b', |
| for instance 'kb' is identical to 'k'. You can specify a base 10 value |
| by using 'KiB', 'MiB', 'GiB', etc. This is useful for disk drives where |
| values are often given in base 10 values. Specifying '30GiB' will get you |
| 30*1000^3 bytes. |
| .TP |
| .I bool |
| Boolean: a true or false value. `0' denotes false, `1' denotes true. |
| .TP |
| .I irange |
| Integer range: a range of integers specified in the format |
| \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and |
| \fIupper\fR may contain a suffix as described above. If an option allows two |
| sets of ranges, they are separated with a `,' or `/' character. For example: |
| `8\-8k/8M\-4G'. |
| .TP |
| .I float_list |
| List of floating numbers: A list of floating numbers, separated by |
| a ':' character. |
| .SS "Parameter List" |
| .TP |
| .BI name \fR=\fPstr |
| May be used to override the job name. On the command line, this parameter |
| has the special purpose of signalling the start of a new job. |
| .TP |
| .BI description \fR=\fPstr |
| Human-readable description of the job. It is printed when the job is run, but |
| otherwise has no special purpose. |
| .TP |
| .BI directory \fR=\fPstr |
| Prefix filenames with this directory. Used to place files in a location other |
| than `./'. |
| .TP |
| .BI filename \fR=\fPstr |
| .B fio |
| normally makes up a file name based on the job name, thread number, and file |
| number. If you want to share files between threads in a job or several jobs, |
| specify a \fIfilename\fR for each of them to override the default. |
| If the I/O engine is file-based, you can specify |
| a number of files by separating the names with a `:' character. `\-' is a |
| reserved name, meaning stdin or stdout, depending on the read/write direction |
| set. |
| .TP |
| .BI filename_format \fR=\fPstr |
| If sharing multiple files between jobs, it is usually necessary to have |
| fio generate the exact names that you want. By default, fio will name a file |
| based on the default file format specification of |
| \fBjobname.jobnumber.filenumber\fP. With this option, that can be |
| customized. Fio will recognize and replace the following keywords in this |
| string: |
| .RS |
| .RS |
| .TP |
| .B $jobname |
| The name of the worker thread or process. |
| .TP |
| .B $jobnum |
| The incremental number of the worker thread or process. |
| .TP |
| .B $filenum |
| The incremental number of the file for that worker thread or process. |
| .RE |
| .P |
| To have dependent jobs share a set of files, this option can be set to |
| have fio generate filenames that are shared between the two. For instance, |
| if \fBtestfiles.$filenum\fR is specified, file number 4 for any job will |
| be named \fBtestfiles.4\fR. The default of \fB$jobname.$jobnum.$filenum\fR |
| will be used if no other format specifier is given. |
| .RE |
| .P |
| .TP |
| .BI lockfile \fR=\fPstr |
| Fio defaults to not locking any files before it does IO to them. If a file or |
| file descriptor is shared, fio can serialize IO to that file to make the end |
| result consistent. This is usual for emulating real workloads that share files. |
| The lock modes are: |
| .RS |
| .RS |
| .TP |
| .B none |
| No locking. This is the default. |
| .TP |
| .B exclusive |
| Only one thread or process may do IO at the time, excluding all others. |
| .TP |
| .B readwrite |
| Read-write locking on the file. Many readers may access the file at the same |
| time, but writes get exclusive access. |
| .RE |
| .RE |
| .P |
| .BI opendir \fR=\fPstr |
| Recursively open any files below directory \fIstr\fR. |
| .TP |
| .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr |
| Type of I/O pattern. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B read |
| Sequential reads. |
| .TP |
| .B write |
| Sequential writes. |
| .TP |
| .B trim |
| Sequential trim (Linux block devices only). |
| .TP |
| .B randread |
| Random reads. |
| .TP |
| .B randwrite |
| Random writes. |
| .TP |
| .B randtrim |
| Random trim (Linux block devices only). |
| .TP |
| .B rw, readwrite |
| Mixed sequential reads and writes. |
| .TP |
| .B randrw |
| Mixed random reads and writes. |
| .RE |
| .P |
| For mixed I/O, the default split is 50/50. For certain types of io the result |
| may still be skewed a bit, since the speed may be different. It is possible to |
| specify a number of IO's to do before getting a new offset, this is done by |
| appending a `:\fI<nr>\fR to the end of the string given. For a random read, it |
| would look like \fBrw=randread:8\fR for passing in an offset modifier with a |
| value of 8. If the postfix is used with a sequential IO pattern, then the value |
| specified will be added to the generated offset for each IO. For instance, |
| using \fBrw=write:4k\fR will skip 4k for every write. It turns sequential IO |
| into sequential IO with holes. See the \fBrw_sequencer\fR option. |
| .RE |
| .TP |
| .BI rw_sequencer \fR=\fPstr |
| If an offset modifier is given by appending a number to the \fBrw=<str>\fR line, |
| then this option controls how that number modifies the IO offset being |
| generated. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B sequential |
| Generate sequential offset |
| .TP |
| .B identical |
| Generate the same offset |
| .RE |
| .P |
| \fBsequential\fR is only useful for random IO, where fio would normally |
| generate a new random offset for every IO. If you append eg 8 to randread, you |
| would get a new random offset for every 8 IO's. The result would be a seek for |
| only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify |
| that. As sequential IO is already sequential, setting \fBsequential\fR for that |
| would not result in any differences. \fBidentical\fR behaves in a similar |
| fashion, except it sends the same offset 8 number of times before generating a |
| new offset. |
| .RE |
| .P |
| .TP |
| .BI kb_base \fR=\fPint |
| The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage |
| manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious |
| reasons. Allowed values are 1024 or 1000, with 1024 being the default. |
| .TP |
| .BI unified_rw_reporting \fR=\fPbool |
| Fio normally reports statistics on a per data direction basis, meaning that |
| read, write, and trim are accounted and reported separately. If this option is |
| set, the fio will sum the results and report them as "mixed" instead. |
| .TP |
| .BI randrepeat \fR=\fPbool |
| Seed the random number generator in a predictable way so results are repeatable |
| across runs. Default: true. |
| .TP |
| .BI use_os_rand \fR=\fPbool |
| Fio can either use the random generator supplied by the OS to generator random |
| offsets, or it can use it's own internal generator (based on Tausworthe). |
| Default is to use the internal generator, which is often of better quality and |
| faster. Default: false. |
| .TP |
| .BI fallocate \fR=\fPstr |
| Whether pre-allocation is performed when laying down files. Accepted values |
| are: |
| .RS |
| .RS |
| .TP |
| .B none |
| Do not pre-allocate space. |
| .TP |
| .B posix |
| Pre-allocate via posix_fallocate(). |
| .TP |
| .B keep |
| Pre-allocate via fallocate() with FALLOC_FL_KEEP_SIZE set. |
| .TP |
| .B 0 |
| Backward-compatible alias for 'none'. |
| .TP |
| .B 1 |
| Backward-compatible alias for 'posix'. |
| .RE |
| .P |
| May not be available on all supported platforms. 'keep' is only |
| available on Linux. If using ZFS on Solaris this must be set to 'none' |
| because ZFS doesn't support it. Default: 'posix'. |
| .RE |
| .TP |
| .BI fadvise_hint \fR=\fPbool |
| Use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns |
| are likely to be issued. Default: true. |
| .TP |
| .BI size \fR=\fPint |
| Total size of I/O for this job. \fBfio\fR will run until this many bytes have |
| been transferred, unless limited by other options (\fBruntime\fR, for instance). |
| Unless \fBnrfiles\fR and \fBfilesize\fR options are given, this amount will be |
| divided between the available files for the job. If not set, fio will use the |
| full size of the given files or devices. If the files do not exist, size |
| must be given. It is also possible to give size as a percentage between 1 and |
| 100. If size=20% is given, fio will use 20% of the full size of the given files |
| or devices. |
| .TP |
| .BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool |
| Sets size to something really large and waits for ENOSPC (no space left on |
| device) as the terminating condition. Only makes sense with sequential write. |
| For a read workload, the mount point will be filled first then IO started on |
| the result. This option doesn't make sense if operating on a raw device node, |
| since the size of that is already known by the file system. Additionally, |
| writing beyond end-of-device will not return ENOSPC there. |
| .TP |
| .BI filesize \fR=\fPirange |
| Individual file sizes. May be a range, in which case \fBfio\fR will select sizes |
| for files at random within the given range, limited to \fBsize\fR in total (if |
| that is given). If \fBfilesize\fR is not specified, each created file is the |
| same size. |
| .TP |
| .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int] |
| Block size for I/O units. Default: 4k. Values for reads, writes, and trims |
| can be specified separately in the format \fIread\fR,\fIwrite\fR,\fItrim\fR |
| either of which may be empty to leave that value at its default. If a trailing |
| comma isn't given, the remainder will inherit the last value set. |
| .TP |
| .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange] |
| Specify a range of I/O block sizes. The issued I/O unit will always be a |
| multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies |
| to both reads and writes if only one range is given, but can be specified |
| separately with a comma separating the values. Example: bsrange=1k-4k,2k-8k. |
| Also (see \fBblocksize\fR). |
| .TP |
| .BI bssplit \fR=\fPstr |
| This option allows even finer grained control of the block sizes issued, |
| not just even splits between them. With this option, you can weight various |
| block sizes for exact control of the issued IO for a job that has mixed |
| block sizes. The format of the option is bssplit=blocksize/percentage, |
| optionally adding as many definitions as needed separated by a colon. |
| Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k |
| blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate |
| splits to reads and writes. The format is identical to what the |
| \fBbs\fR option accepts, the read and write parts are separated with a |
| comma. |
| .TP |
| .B blocksize_unaligned\fR,\fP bs_unaligned |
| If set, any size in \fBblocksize_range\fR may be used. This typically won't |
| work with direct I/O, as that normally requires sector alignment. |
| .TP |
| .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int] |
| At what boundary to align random IO offsets. Defaults to the same as 'blocksize' |
| the minimum blocksize given. Minimum alignment is typically 512b |
| for using direct IO, though it usually depends on the hardware block size. |
| This option is mutually exclusive with using a random map for files, so it |
| will turn off that option. |
| .TP |
| .BI bs_is_seq_rand \fR=\fPbool |
| If this option is set, fio will use the normal read,write blocksize settings as |
| sequential,random instead. Any random read or write will use the WRITE |
| blocksize settings, and any sequential read or write will use the READ |
| blocksize setting. |
| .TP |
| .B zero_buffers |
| Initialise buffers with all zeros. Default: fill buffers with random data. |
| .TP |
| .B refill_buffers |
| If this option is given, fio will refill the IO buffers on every submit. The |
| default is to only fill it at init time and reuse that data. Only makes sense |
| if zero_buffers isn't specified, naturally. If data verification is enabled, |
| refill_buffers is also automatically enabled. |
| .TP |
| .BI scramble_buffers \fR=\fPbool |
| If \fBrefill_buffers\fR is too costly and the target is using data |
| deduplication, then setting this option will slightly modify the IO buffer |
| contents to defeat normal de-dupe attempts. This is not enough to defeat |
| more clever block compression attempts, but it will stop naive dedupe |
| of blocks. Default: true. |
| .TP |
| .BI buffer_compress_percentage \fR=\fPint |
| If this is set, then fio will attempt to provide IO buffer content (on WRITEs) |
| that compress to the specified level. Fio does this by providing a mix of |
| random data and zeroes. Note that this is per block size unit, for file/disk |
| wide compression level that matches this setting, you'll also want to set |
| \fBrefill_buffers\fR. |
| .TP |
| .BI buffer_compress_chunk \fR=\fPint |
| See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how |
| big the ranges of random data and zeroed data is. Without this set, fio will |
| provide \fBbuffer_compress_percentage\fR of blocksize random data, followed by |
| the remaining zeroed. With this set to some chunk size smaller than the block |
| size, fio can alternate random and zeroed data throughout the IO buffer. |
| .TP |
| .BI nrfiles \fR=\fPint |
| Number of files to use for this job. Default: 1. |
| .TP |
| .BI openfiles \fR=\fPint |
| Number of files to keep open at the same time. Default: \fBnrfiles\fR. |
| .TP |
| .BI file_service_type \fR=\fPstr |
| Defines how files to service are selected. The following types are defined: |
| .RS |
| .RS |
| .TP |
| .B random |
| Choose a file at random. |
| .TP |
| .B roundrobin |
| Round robin over open files (default). |
| .TP |
| .B sequential |
| Do each file in the set sequentially. |
| .RE |
| .P |
| The number of I/Os to issue before switching a new file can be specified by |
| appending `:\fIint\fR' to the service type. |
| .RE |
| .TP |
| .BI ioengine \fR=\fPstr |
| Defines how the job issues I/O. The following types are defined: |
| .RS |
| .RS |
| .TP |
| .B sync |
| Basic \fIread\fR\|(2) or \fIwrite\fR\|(2) I/O. \fIfseek\fR\|(2) is used to |
| position the I/O location. |
| .TP |
| .B psync |
| Basic \fIpread\fR\|(2) or \fIpwrite\fR\|(2) I/O. |
| .TP |
| .B vsync |
| Basic \fIreadv\fR\|(2) or \fIwritev\fR\|(2) I/O. Will emulate queuing by |
| coalescing adjacent IOs into a single submission. |
| .TP |
| .B pvsync |
| Basic \fIpreadv\fR\|(2) or \fIpwritev\fR\|(2) I/O. |
| .TP |
| .B libaio |
| Linux native asynchronous I/O. This ioengine defines engine specific options. |
| .TP |
| .B posixaio |
| POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3). |
| .TP |
| .B solarisaio |
| Solaris native asynchronous I/O. |
| .TP |
| .B windowsaio |
| Windows native asynchronous I/O. |
| .TP |
| .B mmap |
| File is memory mapped with \fImmap\fR\|(2) and data copied using |
| \fImemcpy\fR\|(3). |
| .TP |
| .B splice |
| \fIsplice\fR\|(2) is used to transfer the data and \fIvmsplice\fR\|(2) to |
| transfer data from user-space to the kernel. |
| .TP |
| .B syslet-rw |
| Use the syslet system calls to make regular read/write asynchronous. |
| .TP |
| .B sg |
| SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if |
| the target is an sg character device, we use \fIread\fR\|(2) and |
| \fIwrite\fR\|(2) for asynchronous I/O. |
| .TP |
| .B null |
| Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR |
| itself and for debugging and testing purposes. |
| .TP |
| .B net |
| Transfer over the network. The protocol to be used can be defined with the |
| \fBprotocol\fR parameter. Depending on the protocol, \fBfilename\fR, |
| \fBhostname\fR, \fBport\fR, or \fBlisten\fR must be specified. |
| This ioengine defines engine specific options. |
| .TP |
| .B netsplice |
| Like \fBnet\fR, but uses \fIsplice\fR\|(2) and \fIvmsplice\fR\|(2) to map data |
| and send/receive. This ioengine defines engine specific options. |
| .TP |
| .B cpuio |
| Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and |
| \fBcpucycles\fR parameters. |
| .TP |
| .B guasi |
| The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface |
| approach to asynchronous I/O. |
| .br |
| See <http://www.xmailserver.org/guasi\-lib.html>. |
| .TP |
| .B rdma |
| The RDMA I/O engine supports both RDMA memory semantics (RDMA_WRITE/RDMA_READ) |
| and channel semantics (Send/Recv) for the InfiniBand, RoCE and iWARP protocols. |
| .TP |
| .B external |
| Loads an external I/O engine object file. Append the engine filename as |
| `:\fIenginepath\fR'. |
| .TP |
| .B falloc |
| IO engine that does regular linux native fallocate call to simulate data |
| transfer as fio ioengine |
| .br |
| DDIR_READ does fallocate(,mode = FALLOC_FL_KEEP_SIZE,) |
| .br |
| DIR_WRITE does fallocate(,mode = 0) |
| .br |
| DDIR_TRIM does fallocate(,mode = FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE) |
| .TP |
| .B e4defrag |
| IO engine that does regular EXT4_IOC_MOVE_EXT ioctls to simulate defragment activity |
| request to DDIR_WRITE event |
| .RE |
| .P |
| .RE |
| .TP |
| .BI iodepth \fR=\fPint |
| Number of I/O units to keep in flight against the file. Note that increasing |
| iodepth beyond 1 will not affect synchronous ioengines (except for small |
| degress when verify_async is in use). Even async engines my impose OS |
| restrictions causing the desired depth not to be achieved. This may happen on |
| Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is |
| not async on that OS. Keep an eye on the IO depth distribution in the |
| fio output to verify that the achieved depth is as expected. Default: 1. |
| .TP |
| .BI iodepth_batch \fR=\fPint |
| Number of I/Os to submit at once. Default: \fBiodepth\fR. |
| .TP |
| .BI iodepth_batch_complete \fR=\fPint |
| This defines how many pieces of IO to retrieve at once. It defaults to 1 which |
| means that we'll ask for a minimum of 1 IO in the retrieval process from the |
| kernel. The IO retrieval will go on until we hit the limit set by |
| \fBiodepth_low\fR. If this variable is set to 0, then fio will always check for |
| completed events before queuing more IO. This helps reduce IO latency, at the |
| cost of more retrieval system calls. |
| .TP |
| .BI iodepth_low \fR=\fPint |
| Low watermark indicating when to start filling the queue again. Default: |
| \fBiodepth\fR. |
| .TP |
| .BI direct \fR=\fPbool |
| If true, use non-buffered I/O (usually O_DIRECT). Default: false. |
| .TP |
| .BI buffered \fR=\fPbool |
| If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter. |
| Default: true. |
| .TP |
| .BI offset \fR=\fPint |
| Offset in the file to start I/O. Data before the offset will not be touched. |
| .TP |
| .BI offset_increment \fR=\fPint |
| If this is provided, then the real offset becomes the |
| offset + offset_increment * thread_number, where the thread number is a counter |
| that starts at 0 and is incremented for each job. This option is useful if |
| there are several jobs which are intended to operate on a file in parallel in |
| disjoint segments, with even spacing between the starting points. |
| .TP |
| .BI number_ios \fR=\fPint |
| Fio will normally perform IOs until it has exhausted the size of the region |
| set by \fBsize\fR, or if it exhaust the allocated time (or hits an error |
| condition). With this setting, the range/size can be set independently of |
| the number of IOs to perform. When fio reaches this number, it will exit |
| normally and report status. |
| .TP |
| .BI fsync \fR=\fPint |
| How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If |
| 0, don't sync. Default: 0. |
| .TP |
| .BI fdatasync \fR=\fPint |
| Like \fBfsync\fR, but uses \fBfdatasync\fR\|(2) instead to only sync the |
| data parts of the file. Default: 0. |
| .TP |
| .BI write_barrier \fR=\fPint |
| Make every Nth write a barrier write. |
| .TP |
| .BI sync_file_range \fR=\fPstr:int |
| Use sync_file_range() for every \fRval\fP number of write operations. Fio will |
| track range of writes that have happened since the last sync_file_range() call. |
| \fRstr\fP can currently be one or more of: |
| .RS |
| .TP |
| .B wait_before |
| SYNC_FILE_RANGE_WAIT_BEFORE |
| .TP |
| .B write |
| SYNC_FILE_RANGE_WRITE |
| .TP |
| .B wait_after |
| SYNC_FILE_RANGE_WRITE |
| .TP |
| .RE |
| .P |
| So if you do sync_file_range=wait_before,write:8, fio would use |
| \fBSYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE\fP for every 8 writes. |
| Also see the sync_file_range(2) man page. This option is Linux specific. |
| .TP |
| .BI overwrite \fR=\fPbool |
| If writing, setup the file first and do overwrites. Default: false. |
| .TP |
| .BI end_fsync \fR=\fPbool |
| Sync file contents when a write stage has completed. Default: false. |
| .TP |
| .BI fsync_on_close \fR=\fPbool |
| If true, sync file contents on close. This differs from \fBend_fsync\fR in that |
| it will happen on every close, not just at the end of the job. Default: false. |
| .TP |
| .BI rwmixread \fR=\fPint |
| Percentage of a mixed workload that should be reads. Default: 50. |
| .TP |
| .BI rwmixwrite \fR=\fPint |
| Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and |
| \fBrwmixwrite\fR are given and do not sum to 100%, the latter of the two |
| overrides the first. This may interfere with a given rate setting, if fio is |
| asked to limit reads or writes to a certain rate. If that is the case, then |
| the distribution may be skewed. Default: 50. |
| .TP |
| .BI random_distribution \fR=\fPstr:float |
| By default, fio will use a completely uniform random distribution when asked |
| to perform random IO. Sometimes it is useful to skew the distribution in |
| specific ways, ensuring that some parts of the data is more hot than others. |
| Fio includes the following distribution models: |
| .RS |
| .TP |
| .B random |
| Uniform random distribution |
| .TP |
| .B zipf |
| Zipf distribution |
| .TP |
| .B pareto |
| Pareto distribution |
| .TP |
| .RE |
| .P |
| When using a zipf or pareto distribution, an input value is also needed to |
| define the access pattern. For zipf, this is the zipf theta. For pareto, |
| it's the pareto power. Fio includes a test program, genzipf, that can be |
| used visualize what the given input values will yield in terms of hit rates. |
| If you wanted to use zipf with a theta of 1.2, you would use |
| random_distribution=zipf:1.2 as the option. If a non-uniform model is used, |
| fio will disable use of the random map. |
| .TP |
| .BI percentage_random \fR=\fPint |
| For a random workload, set how big a percentage should be random. This defaults |
| to 100%, in which case the workload is fully random. It can be set from |
| anywhere from 0 to 100. Setting it to 0 would make the workload fully |
| sequential. It is possible to set different values for reads, writes, and |
| trim. To do so, simply use a comma separated list. See \fBblocksize\fR. |
| .TP |
| .B norandommap |
| Normally \fBfio\fR will cover every block of the file when doing random I/O. If |
| this parameter is given, a new offset will be chosen without looking at past |
| I/O history. This parameter is mutually exclusive with \fBverify\fR. |
| .TP |
| .BI softrandommap \fR=\fPbool |
| See \fBnorandommap\fR. If fio runs with the random block map enabled and it |
| fails to allocate the map, if this option is set it will continue without a |
| random block map. As coverage will not be as complete as with random maps, this |
| option is disabled by default. |
| .TP |
| .BI random_generator \fR=\fPstr |
| Fio supports the following engines for generating IO offsets for random IO: |
| .RS |
| .TP |
| .B tausworthe |
| Strong 2^88 cycle random number generator |
| .TP |
| .B lfsr |
| Linear feedback shift register generator |
| .TP |
| .RE |
| .P |
| Tausworthe is a strong random number generator, but it requires tracking on the |
| side if we want to ensure that blocks are only read or written once. LFSR |
| guarantees that we never generate the same offset twice, and it's also less |
| computationally expensive. It's not a true random generator, however, though |
| for IO purposes it's typically good enough. LFSR only works with single block |
| sizes, not with workloads that use multiple block sizes. If used with such a |
| workload, fio may read or write some blocks multiple times. |
| .TP |
| .BI nice \fR=\fPint |
| Run job with given nice value. See \fInice\fR\|(2). |
| .TP |
| .BI prio \fR=\fPint |
| Set I/O priority value of this job between 0 (highest) and 7 (lowest). See |
| \fIionice\fR\|(1). |
| .TP |
| .BI prioclass \fR=\fPint |
| Set I/O priority class. See \fIionice\fR\|(1). |
| .TP |
| .BI thinktime \fR=\fPint |
| Stall job for given number of microseconds between issuing I/Os. |
| .TP |
| .BI thinktime_spin \fR=\fPint |
| Pretend to spend CPU time for given number of microseconds, sleeping the rest |
| of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set. |
| .TP |
| .BI thinktime_blocks \fR=\fPint |
| Only valid if thinktime is set - control how many blocks to issue, before |
| waiting \fBthinktime\fR microseconds. If not set, defaults to 1 which will |
| make fio wait \fBthinktime\fR microseconds after every block. This |
| effectively makes any queue depth setting redundant, since no more than 1 IO |
| will be queued before we have to complete it and do our thinktime. In other |
| words, this setting effectively caps the queue depth if the latter is larger. |
| Default: 1. |
| .TP |
| .BI rate \fR=\fPint |
| Cap bandwidth used by this job. The number is in bytes/sec, the normal postfix |
| rules apply. You can use \fBrate\fR=500k to limit reads and writes to 500k each, |
| or you can specify read and writes separately. Using \fBrate\fR=1m,500k would |
| limit reads to 1MB/sec and writes to 500KB/sec. Capping only reads or writes |
| can be done with \fBrate\fR=,500k or \fBrate\fR=500k,. The former will only |
| limit writes (to 500KB/sec), the latter will only limit reads. |
| .TP |
| .BI ratemin \fR=\fPint |
| Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth. |
| Failing to meet this requirement will cause the job to exit. The same format |
| as \fBrate\fR is used for read vs write separation. |
| .TP |
| .BI rate_iops \fR=\fPint |
| Cap the bandwidth to this number of IOPS. Basically the same as rate, just |
| specified independently of bandwidth. The same format as \fBrate\fR is used for |
| read vs write separation. If \fBblocksize\fR is a range, the smallest block |
| size is used as the metric. |
| .TP |
| .BI rate_iops_min \fR=\fPint |
| If this rate of I/O is not met, the job will exit. The same format as \fBrate\fR |
| is used for read vs write separation. |
| .TP |
| .BI ratecycle \fR=\fPint |
| Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of |
| milliseconds. Default: 1000ms. |
| .TP |
| .BI max_latency \fR=\fPint |
| If set, fio will exit the job if it exceeds this maximum latency. It will exit |
| with an ETIME error. |
| .TP |
| .BI cpumask \fR=\fPint |
| Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job |
| may run on. See \fBsched_setaffinity\fR\|(2). |
| .TP |
| .BI cpus_allowed \fR=\fPstr |
| Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers. |
| .TP |
| .BI numa_cpu_nodes \fR=\fPstr |
| Set this job running on specified NUMA nodes' CPUs. The arguments allow |
| comma delimited list of cpu numbers, A-B ranges, or 'all'. |
| .TP |
| .BI numa_mem_policy \fR=\fPstr |
| Set this job's memory policy and corresponding NUMA nodes. Format of |
| the arguments: |
| .RS |
| .TP |
| .B <mode>[:<nodelist>] |
| .TP |
| .B mode |
| is one of the following memory policy: |
| .TP |
| .B default, prefer, bind, interleave, local |
| .TP |
| .RE |
| For \fBdefault\fR and \fBlocal\fR memory policy, no \fBnodelist\fR is |
| needed to be specified. For \fBprefer\fR, only one node is |
| allowed. For \fBbind\fR and \fBinterleave\fR, \fBnodelist\fR allows |
| comma delimited list of numbers, A-B ranges, or 'all'. |
| .TP |
| .BI startdelay \fR=\fPint |
| Delay start of job for the specified number of seconds. |
| .TP |
| .BI runtime \fR=\fPint |
| Terminate processing after the specified number of seconds. |
| .TP |
| .B time_based |
| If given, run for the specified \fBruntime\fR duration even if the files are |
| completely read or written. The same workload will be repeated as many times |
| as \fBruntime\fR allows. |
| .TP |
| .BI ramp_time \fR=\fPint |
| If set, fio will run the specified workload for this amount of time before |
| logging any performance numbers. Useful for letting performance settle before |
| logging results, thus minimizing the runtime required for stable results. Note |
| that the \fBramp_time\fR is considered lead in time for a job, thus it will |
| increase the total runtime if a special timeout or runtime is specified. |
| .TP |
| .BI invalidate \fR=\fPbool |
| Invalidate buffer-cache for the file prior to starting I/O. Default: true. |
| .TP |
| .BI sync \fR=\fPbool |
| Use synchronous I/O for buffered writes. For the majority of I/O engines, |
| this means using O_SYNC. Default: false. |
| .TP |
| .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr |
| Allocation method for I/O unit buffer. Allowed values are: |
| .RS |
| .RS |
| .TP |
| .B malloc |
| Allocate memory with \fImalloc\fR\|(3). |
| .TP |
| .B shm |
| Use shared memory buffers allocated through \fIshmget\fR\|(2). |
| .TP |
| .B shmhuge |
| Same as \fBshm\fR, but use huge pages as backing. |
| .TP |
| .B mmap |
| Use \fImmap\fR\|(2) for allocation. Uses anonymous memory unless a filename |
| is given after the option in the format `:\fIfile\fR'. |
| .TP |
| .B mmaphuge |
| Same as \fBmmap\fR, but use huge files as backing. |
| .RE |
| .P |
| The amount of memory allocated is the maximum allowed \fBblocksize\fR for the |
| job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work, |
| the system must have free huge pages allocated. \fBmmaphuge\fR also needs to |
| have hugetlbfs mounted, and \fIfile\fR must point there. At least on Linux, |
| huge pages must be manually allocated. See \fB/proc/sys/vm/nr_hugehages\fR |
| and the documentation for that. Normally you just need to echo an appropriate |
| number, eg echoing 8 will ensure that the OS has 8 huge pages ready for |
| use. |
| .RE |
| .TP |
| .BI iomem_align \fR=\fPint "\fR,\fP mem_align" \fR=\fPint |
| This indicates the memory alignment of the IO memory buffers. Note that the |
| given alignment is applied to the first IO unit buffer, if using \fBiodepth\fR |
| the alignment of the following buffers are given by the \fBbs\fR used. In |
| other words, if using a \fBbs\fR that is a multiple of the page sized in the |
| system, all buffers will be aligned to this value. If using a \fBbs\fR that |
| is not page aligned, the alignment of subsequent IO memory buffers is the |
| sum of the \fBiomem_align\fR and \fBbs\fR used. |
| .TP |
| .BI hugepage\-size \fR=\fPint |
| Defines the size of a huge page. Must be at least equal to the system setting. |
| Should be a multiple of 1MB. Default: 4MB. |
| .TP |
| .B exitall |
| Terminate all jobs when one finishes. Default: wait for each job to finish. |
| .TP |
| .BI bwavgtime \fR=\fPint |
| Average bandwidth calculations over the given time in milliseconds. Default: |
| 500ms. |
| .TP |
| .BI iopsavgtime \fR=\fPint |
| Average IOPS calculations over the given time in milliseconds. Default: |
| 500ms. |
| .TP |
| .BI create_serialize \fR=\fPbool |
| If true, serialize file creation for the jobs. Default: true. |
| .TP |
| .BI create_fsync \fR=\fPbool |
| \fIfsync\fR\|(2) data file after creation. Default: true. |
| .TP |
| .BI create_on_open \fR=\fPbool |
| If true, the files are not created until they are opened for IO by the job. |
| .TP |
| .BI create_only \fR=\fPbool |
| If true, fio will only run the setup phase of the job. If files need to be |
| laid out or updated on disk, only that will be done. The actual job contents |
| are not executed. |
| .TP |
| .BI pre_read \fR=\fPbool |
| If this is given, files will be pre-read into memory before starting the given |
| IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is |
| pointless to pre-read and then drop the cache. This will only work for IO |
| engines that are seekable, since they allow you to read the same data |
| multiple times. Thus it will not work on eg network or splice IO. |
| .TP |
| .BI unlink \fR=\fPbool |
| Unlink job files when done. Default: false. |
| .TP |
| .BI loops \fR=\fPint |
| Specifies the number of iterations (runs of the same workload) of this job. |
| Default: 1. |
| .TP |
| .BI do_verify \fR=\fPbool |
| Run the verify phase after a write phase. Only valid if \fBverify\fR is set. |
| Default: true. |
| .TP |
| .BI verify \fR=\fPstr |
| Method of verifying file contents after each iteration of the job. Allowed |
| values are: |
| .RS |
| .RS |
| .TP |
| .B md5 crc16 crc32 crc32c crc32c-intel crc64 crc7 sha256 sha512 sha1 |
| Store appropriate checksum in the header of each block. crc32c-intel is |
| hardware accelerated SSE4.2 driven, falls back to regular crc32c if |
| not supported by the system. |
| .TP |
| .B meta |
| Write extra information about each I/O (timestamp, block number, etc.). The |
| block number is verified. See \fBverify_pattern\fR as well. |
| .TP |
| .B null |
| Pretend to verify. Used for testing internals. |
| .RE |
| |
| This option can be used for repeated burn-in tests of a system to make sure |
| that the written data is also correctly read back. If the data direction given |
| is a read or random read, fio will assume that it should verify a previously |
| written file. If the data direction includes any form of write, the verify will |
| be of the newly written data. |
| .RE |
| .TP |
| .BI verifysort \fR=\fPbool |
| If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to |
| read them back in a sorted manner. Default: true. |
| .TP |
| .BI verifysort_nr \fR=\fPint |
| Pre-load and sort verify blocks for a read workload. |
| .TP |
| .BI verify_offset \fR=\fPint |
| Swap the verification header with data somewhere else in the block before |
| writing. It is swapped back before verifying. |
| .TP |
| .BI verify_interval \fR=\fPint |
| Write the verification header for this number of bytes, which should divide |
| \fBblocksize\fR. Default: \fBblocksize\fR. |
| .TP |
| .BI verify_pattern \fR=\fPstr |
| If set, fio will fill the io buffers with this pattern. Fio defaults to filling |
| with totally random bytes, but sometimes it's interesting to fill with a known |
| pattern for io verification purposes. Depending on the width of the pattern, |
| fio will fill 1/2/3/4 bytes of the buffer at the time(it can be either a |
| decimal or a hex number). The verify_pattern if larger than a 32-bit quantity |
| has to be a hex number that starts with either "0x" or "0X". Use with |
| \fBverify\fP=meta. |
| .TP |
| .BI verify_fatal \fR=\fPbool |
| If true, exit the job on the first observed verification failure. Default: |
| false. |
| .TP |
| .BI verify_dump \fR=\fPbool |
| If set, dump the contents of both the original data block and the data block we |
| read off disk to files. This allows later analysis to inspect just what kind of |
| data corruption occurred. Off by default. |
| .TP |
| .BI verify_async \fR=\fPint |
| Fio will normally verify IO inline from the submitting thread. This option |
| takes an integer describing how many async offload threads to create for IO |
| verification instead, causing fio to offload the duty of verifying IO contents |
| to one or more separate threads. If using this offload option, even sync IO |
| engines can benefit from using an \fBiodepth\fR setting higher than 1, as it |
| allows them to have IO in flight while verifies are running. |
| .TP |
| .BI verify_async_cpus \fR=\fPstr |
| Tell fio to set the given CPU affinity on the async IO verification threads. |
| See \fBcpus_allowed\fP for the format used. |
| .TP |
| .BI verify_backlog \fR=\fPint |
| Fio will normally verify the written contents of a job that utilizes verify |
| once that job has completed. In other words, everything is written then |
| everything is read back and verified. You may want to verify continually |
| instead for a variety of reasons. Fio stores the meta data associated with an |
| IO block in memory, so for large verify workloads, quite a bit of memory would |
| be used up holding this meta data. If this option is enabled, fio will write |
| only N blocks before verifying these blocks. |
| .TP |
| .BI verify_backlog_batch \fR=\fPint |
| Control how many blocks fio will verify if verify_backlog is set. If not set, |
| will default to the value of \fBverify_backlog\fR (meaning the entire queue is |
| read back and verified). If \fBverify_backlog_batch\fR is less than |
| \fBverify_backlog\fR then not all blocks will be verified, if |
| \fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks |
| will be verified more than once. |
| .TP |
| .BI trim_percentage \fR=\fPint |
| Number of verify blocks to discard/trim. |
| .TP |
| .BI trim_verify_zero \fR=\fPbool |
| Verify that trim/discarded blocks are returned as zeroes. |
| .TP |
| .BI trim_backlog \fR=\fPint |
| Trim after this number of blocks are written. |
| .TP |
| .BI trim_backlog_batch \fR=\fPint |
| Trim this number of IO blocks. |
| .TP |
| .BI experimental_verify \fR=\fPbool |
| Enable experimental verification. |
| .TP |
| .B stonewall "\fR,\fP wait_for_previous" |
| Wait for preceding jobs in the job file to exit before starting this one. |
| \fBstonewall\fR implies \fBnew_group\fR. |
| .TP |
| .B new_group |
| Start a new reporting group. If not given, all jobs in a file will be part |
| of the same reporting group, unless separated by a stonewall. |
| .TP |
| .BI numjobs \fR=\fPint |
| Number of clones (processes/threads performing the same workload) of this job. |
| Default: 1. |
| .TP |
| .B group_reporting |
| If set, display per-group reports instead of per-job when \fBnumjobs\fR is |
| specified. |
| .TP |
| .B thread |
| Use threads created with \fBpthread_create\fR\|(3) instead of processes created |
| with \fBfork\fR\|(2). |
| .TP |
| .BI zonesize \fR=\fPint |
| Divide file into zones of the specified size in bytes. See \fBzoneskip\fR. |
| .TP |
| .BI zonerange \fR=\fPint |
| Give size of an IO zone. See \fBzoneskip\fR. |
| .TP |
| .BI zoneskip \fR=\fPint |
| Skip the specified number of bytes when \fBzonesize\fR bytes of data have been |
| read. |
| .TP |
| .BI write_iolog \fR=\fPstr |
| Write the issued I/O patterns to the specified file. Specify a separate file |
| for each job, otherwise the iologs will be interspersed and the file may be |
| corrupt. |
| .TP |
| .BI read_iolog \fR=\fPstr |
| Replay the I/O patterns contained in the specified file generated by |
| \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file. |
| .TP |
| .BI replay_no_stall \fR=\fPint |
| While replaying I/O patterns using \fBread_iolog\fR the default behavior |
| attempts to respect timing information between I/Os. Enabling |
| \fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while |
| still respecting ordering. |
| .TP |
| .BI replay_redirect \fR=\fPstr |
| While replaying I/O patterns using \fBread_iolog\fR the default behavior |
| is to replay the IOPS onto the major/minor device that each IOP was recorded |
| from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the |
| single specified device regardless of the device it was recorded from. |
| .TP |
| .BI write_bw_log \fR=\fPstr |
| If given, write a bandwidth log of the jobs in this job file. Can be used to |
| store data of the bandwidth of the jobs in their lifetime. The included |
| fio_generate_plots script uses gnuplot to turn these text files into nice |
| graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this |
| option, the postfix is _bw.log. |
| .TP |
| .BI write_lat_log \fR=\fPstr |
| Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no |
| filename is given with this option, the default filename of "jobname_type.log" |
| is used. Even if the filename is given, fio will still append the type of log. |
| .TP |
| .BI write_iops_log \fR=\fPstr |
| Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this |
| option, the default filename of "jobname_type.log" is used. Even if the |
| filename is given, fio will still append the type of log. |
| .TP |
| .BI log_avg_msec \fR=\fPint |
| By default, fio will log an entry in the iops, latency, or bw log for every |
| IO that completes. When writing to the disk log, that can quickly grow to a |
| very large size. Setting this option makes fio average the each log entry |
| over the specified period of time, reducing the resolution of the log. |
| Defaults to 0. |
| .TP |
| .BI disable_lat \fR=\fPbool |
| Disable measurements of total latency numbers. Useful only for cutting |
| back the number of calls to gettimeofday, as that does impact performance at |
| really high IOPS rates. Note that to really get rid of a large amount of these |
| calls, this option must be used with disable_slat and disable_bw as well. |
| .TP |
| .BI disable_clat \fR=\fPbool |
| Disable measurements of completion latency numbers. See \fBdisable_lat\fR. |
| .TP |
| .BI disable_slat \fR=\fPbool |
| Disable measurements of submission latency numbers. See \fBdisable_lat\fR. |
| .TP |
| .BI disable_bw_measurement \fR=\fPbool |
| Disable measurements of throughput/bandwidth numbers. See \fBdisable_lat\fR. |
| .TP |
| .BI lockmem \fR=\fPint |
| Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to |
| simulate a smaller amount of memory. The amount specified is per worker. |
| .TP |
| .BI exec_prerun \fR=\fPstr |
| Before running the job, execute the specified command with \fBsystem\fR\|(3). |
| .RS |
| Output is redirected in a file called \fBjobname.prerun.txt\fR |
| .RE |
| .TP |
| .BI exec_postrun \fR=\fPstr |
| Same as \fBexec_prerun\fR, but the command is executed after the job completes. |
| .RS |
| Output is redirected in a file called \fBjobname.postrun.txt\fR |
| .RE |
| .TP |
| .BI ioscheduler \fR=\fPstr |
| Attempt to switch the device hosting the file to the specified I/O scheduler. |
| .TP |
| .BI cpuload \fR=\fPint |
| If the job is a CPU cycle-eater, attempt to use the specified percentage of |
| CPU cycles. |
| .TP |
| .BI cpuchunks \fR=\fPint |
| If the job is a CPU cycle-eater, split the load into cycles of the |
| given time in milliseconds. |
| .TP |
| .BI disk_util \fR=\fPbool |
| Generate disk utilization statistics if the platform supports it. Default: true. |
| .TP |
| .BI clocksource \fR=\fPstr |
| Use the given clocksource as the base of timing. The supported options are: |
| .RS |
| .TP |
| .B gettimeofday |
| gettimeofday(2) |
| .TP |
| .B clock_gettime |
| clock_gettime(2) |
| .TP |
| .B cpu |
| Internal CPU clock source |
| .TP |
| .RE |
| .P |
| \fBcpu\fR is the preferred clocksource if it is reliable, as it is very fast |
| (and fio is heavy on time calls). Fio will automatically use this clocksource |
| if it's supported and considered reliable on the system it is running on, |
| unless another clocksource is specifically set. For x86/x86-64 CPUs, this |
| means supporting TSC Invariant. |
| .TP |
| .BI gtod_reduce \fR=\fPbool |
| Enable all of the gettimeofday() reducing options (disable_clat, disable_slat, |
| disable_bw) plus reduce precision of the timeout somewhat to really shrink the |
| gettimeofday() call count. With this option enabled, we only do about 0.4% of |
| the gtod() calls we would have done if all time keeping was enabled. |
| .TP |
| .BI gtod_cpu \fR=\fPint |
| Sometimes it's cheaper to dedicate a single thread of execution to just getting |
| the current time. Fio (and databases, for instance) are very intensive on |
| gettimeofday() calls. With this option, you can set one CPU aside for doing |
| nothing but logging current time to a shared memory location. Then the other |
| threads/processes that run IO workloads need only copy that segment, instead of |
| entering the kernel with a gettimeofday() call. The CPU set aside for doing |
| these time calls will be excluded from other uses. Fio will manually clear it |
| from the CPU mask of other jobs. |
| .TP |
| .BI ignore_error \fR=\fPstr |
| Sometimes you want to ignore some errors during test in that case you can specify |
| error list for each error type. |
| .br |
| ignore_error=READ_ERR_LIST,WRITE_ERR_LIST,VERIFY_ERR_LIST |
| .br |
| errors for given error type is separated with ':'. |
| Error may be symbol ('ENOSPC', 'ENOMEM') or an integer. |
| .br |
| Example: ignore_error=EAGAIN,ENOSPC:122 . |
| .br |
| This option will ignore EAGAIN from READ, and ENOSPC and 122(EDQUOT) from WRITE. |
| .TP |
| .BI error_dump \fR=\fPbool |
| If set dump every error even if it is non fatal, true by default. If disabled |
| only fatal error will be dumped |
| .TP |
| .BI profile \fR=\fPstr |
| Select a specific builtin performance test. |
| .TP |
| .BI cgroup \fR=\fPstr |
| Add job to this control group. If it doesn't exist, it will be created. |
| The system must have a mounted cgroup blkio mount point for this to work. If |
| your system doesn't have it mounted, you can do so with: |
| |
| # mount \-t cgroup \-o blkio none /cgroup |
| .TP |
| .BI cgroup_weight \fR=\fPint |
| Set the weight of the cgroup to this value. See the documentation that comes |
| with the kernel, allowed values are in the range of 100..1000. |
| .TP |
| .BI cgroup_nodelete \fR=\fPbool |
| Normally fio will delete the cgroups it has created after the job completion. |
| To override this behavior and to leave cgroups around after the job completion, |
| set cgroup_nodelete=1. This can be useful if one wants to inspect various |
| cgroup files after job completion. Default: false |
| .TP |
| .BI uid \fR=\fPint |
| Instead of running as the invoking user, set the user ID to this value before |
| the thread/process does any work. |
| .TP |
| .BI gid \fR=\fPint |
| Set group ID, see \fBuid\fR. |
| .TP |
| .BI unit_base \fR=\fPint |
| Base unit for reporting. Allowed values are: |
| .RS |
| .TP |
| .B 0 |
| Use auto-detection (default). |
| .TP |
| .B 8 |
| Byte based. |
| .TP |
| .B 1 |
| Bit based. |
| .RE |
| .P |
| .TP |
| .BI flow_id \fR=\fPint |
| The ID of the flow. If not specified, it defaults to being a global flow. See |
| \fBflow\fR. |
| .TP |
| .BI flow \fR=\fPint |
| Weight in token-based flow control. If this value is used, then there is a |
| \fBflow counter\fR which is used to regulate the proportion of activity between |
| two or more jobs. fio attempts to keep this flow counter near zero. The |
| \fBflow\fR parameter stands for how much should be added or subtracted to the |
| flow counter on each iteration of the main I/O loop. That is, if one job has |
| \fBflow=8\fR and another job has \fBflow=-1\fR, then there will be a roughly |
| 1:8 ratio in how much one runs vs the other. |
| .TP |
| .BI flow_watermark \fR=\fPint |
| The maximum value that the absolute value of the flow counter is allowed to |
| reach before the job must wait for a lower value of the counter. |
| .TP |
| .BI flow_sleep \fR=\fPint |
| The period of time, in microseconds, to wait after the flow watermark has been |
| exceeded before retrying operations |
| .TP |
| .BI clat_percentiles \fR=\fPbool |
| Enable the reporting of percentiles of completion latencies. |
| .TP |
| .BI percentile_list \fR=\fPfloat_list |
| Overwrite the default list of percentiles for completion |
| latencies. Each number is a floating number in the range (0,100], and |
| the maximum length of the list is 20. Use ':' to separate the |
| numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to |
| report the values of completion latency below which 99.5% and 99.9% of |
| the observed latencies fell, respectively. |
| .SS "Ioengine Parameters List" |
| Some parameters are only valid when a specific ioengine is in use. These are |
| used identically to normal parameters, with the caveat that when used on the |
| command line, the must come after the ioengine that defines them is selected. |
| .TP |
| .BI (cpu)cpuload \fR=\fPint |
| Attempt to use the specified percentage of CPU cycles. |
| .TP |
| .BI (cpu)cpuchunks \fR=\fPint |
| Split the load into cycles of the given time. In microseconds. |
| .TP |
| .BI (libaio)userspace_reap |
| Normally, with the libaio engine in use, fio will use |
| the io_getevents system call to reap newly returned events. |
| With this flag turned on, the AIO ring will be read directly |
| from user-space to reap events. The reaping mode is only |
| enabled when polling for a minimum of 0 events (eg when |
| iodepth_batch_complete=0). |
| .TP |
| .BI (net,netsplice)hostname \fR=\fPstr |
| The host name or IP address to use for TCP or UDP based IO. |
| If the job is a TCP listener or UDP reader, the hostname is not |
| used and must be omitted unless it is a valid UDP multicast address. |
| .TP |
| .BI (net,netsplice)port \fR=\fPint |
| The TCP or UDP port to bind to or connect to. |
| .TP |
| .BI (net,netsplice)interface \fR=\fPstr |
| The IP address of the network interface used to send or receive UDP multicast |
| packets. |
| .TP |
| .BI (net,netsplice)ttl \fR=\fPint |
| Time-to-live value for outgoing UDP multicast packets. Default: 1 |
| .TP |
| .BI (net,netsplice)nodelay \fR=\fPbool |
| Set TCP_NODELAY on TCP connections. |
| .TP |
| .BI (net,netsplice)protocol \fR=\fPstr "\fR,\fP proto" \fR=\fPstr |
| The network protocol to use. Accepted values are: |
| .RS |
| .RS |
| .TP |
| .B tcp |
| Transmission control protocol |
| .TP |
| .B udp |
| User datagram protocol |
| .TP |
| .B unix |
| UNIX domain socket |
| .RE |
| .P |
| When the protocol is TCP or UDP, the port must also be given, |
| as well as the hostname if the job is a TCP listener or UDP |
| reader. For unix sockets, the normal filename option should be |
| used and the port is invalid. |
| .RE |
| .TP |
| .BI (net,netsplice)listen |
| For TCP network connections, tell fio to listen for incoming |
| connections rather than initiating an outgoing connection. The |
| hostname must be omitted if this option is used. |
| .TP |
| .BI (net, pingpong) \fR=\fPbool |
| Normally a network writer will just continue writing data, and a network reader |
| will just consume packages. If pingpong=1 is set, a writer will send its normal |
| payload to the reader, then wait for the reader to send the same payload back. |
| This allows fio to measure network latencies. The submission and completion |
| latencies then measure local time spent sending or receiving, and the |
| completion latency measures how long it took for the other end to receive and |
| send back. For UDP multicast traffic pingpong=1 should only be set for a single |
| reader when multiple readers are listening to the same address. |
| .TP |
| .BI (e4defrag,donorname) \fR=\fPstr |
| File will be used as a block donor (swap extents between files) |
| .TP |
| .BI (e4defrag,inplace) \fR=\fPint |
| Configure donor file block allocation strategy |
| .RS |
| .BI 0(default) : |
| Preallocate donor's file on init |
| .TP |
| .BI 1: |
| allocate space immediately inside defragment event, and free right after event |
| .RE |
| .TP |
| .SH OUTPUT |
| While running, \fBfio\fR will display the status of the created jobs. For |
| example: |
| .RS |
| .P |
| Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s] |
| .RE |
| .P |
| The characters in the first set of brackets denote the current status of each |
| threads. The possible values are: |
| .P |
| .PD 0 |
| .RS |
| .TP |
| .B P |
| Setup but not started. |
| .TP |
| .B C |
| Thread created. |
| .TP |
| .B I |
| Initialized, waiting. |
| .TP |
| .B R |
| Running, doing sequential reads. |
| .TP |
| .B r |
| Running, doing random reads. |
| .TP |
| .B W |
| Running, doing sequential writes. |
| .TP |
| .B w |
| Running, doing random writes. |
| .TP |
| .B M |
| Running, doing mixed sequential reads/writes. |
| .TP |
| .B m |
| Running, doing mixed random reads/writes. |
| .TP |
| .B F |
| Running, currently waiting for \fBfsync\fR\|(2). |
| .TP |
| .B V |
| Running, verifying written data. |
| .TP |
| .B E |
| Exited, not reaped by main thread. |
| .TP |
| .B \- |
| Exited, thread reaped. |
| .RE |
| .PD |
| .P |
| The second set of brackets shows the estimated completion percentage of |
| the current group. The third set shows the read and write I/O rate, |
| respectively. Finally, the estimated run time of the job is displayed. |
| .P |
| When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data |
| for each thread, each group of threads, and each disk, in that order. |
| .P |
| Per-thread statistics first show the threads client number, group-id, and |
| error code. The remaining figures are as follows: |
| .RS |
| .TP |
| .B io |
| Number of megabytes of I/O performed. |
| .TP |
| .B bw |
| Average data rate (bandwidth). |
| .TP |
| .B runt |
| Threads run time. |
| .TP |
| .B slat |
| Submission latency minimum, maximum, average and standard deviation. This is |
| the time it took to submit the I/O. |
| .TP |
| .B clat |
| Completion latency minimum, maximum, average and standard deviation. This |
| is the time between submission and completion. |
| .TP |
| .B bw |
| Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average |
| and standard deviation. |
| .TP |
| .B cpu |
| CPU usage statistics. Includes user and system time, number of context switches |
| this thread went through and number of major and minor page faults. |
| .TP |
| .B IO depths |
| Distribution of I/O depths. Each depth includes everything less than (or equal) |
| to it, but greater than the previous depth. |
| .TP |
| .B IO issued |
| Number of read/write requests issued, and number of short read/write requests. |
| .TP |
| .B IO latencies |
| Distribution of I/O completion latencies. The numbers follow the same pattern |
| as \fBIO depths\fR. |
| .RE |
| .P |
| The group statistics show: |
| .PD 0 |
| .RS |
| .TP |
| .B io |
| Number of megabytes I/O performed. |
| .TP |
| .B aggrb |
| Aggregate bandwidth of threads in the group. |
| .TP |
| .B minb |
| Minimum average bandwidth a thread saw. |
| .TP |
| .B maxb |
| Maximum average bandwidth a thread saw. |
| .TP |
| .B mint |
| Shortest runtime of threads in the group. |
| .TP |
| .B maxt |
| Longest runtime of threads in the group. |
| .RE |
| .PD |
| .P |
| Finally, disk statistics are printed with reads first: |
| .PD 0 |
| .RS |
| .TP |
| .B ios |
| Number of I/Os performed by all groups. |
| .TP |
| .B merge |
| Number of merges in the I/O scheduler. |
| .TP |
| .B ticks |
| Number of ticks we kept the disk busy. |
| .TP |
| .B io_queue |
| Total time spent in the disk queue. |
| .TP |
| .B util |
| Disk utilization. |
| .RE |
| .PD |
| .P |
| It is also possible to get fio to dump the current output while it is |
| running, without terminating the job. To do that, send fio the \fBUSR1\fR |
| signal. |
| .SH TERSE OUTPUT |
| If the \fB\-\-minimal\fR option is given, the results will be printed in a |
| semicolon-delimited format suitable for scripted use - a job description |
| (if provided) follows on a new line. Note that the first |
| number in the line is the version number. If the output has to be changed |
| for some reason, this number will be incremented by 1 to signify that |
| change. The fields are: |
| .P |
| .RS |
| .B terse version, fio version, jobname, groupid, error |
| .P |
| Read status: |
| .RS |
| .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP |
| .P |
| Submission latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Completion latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Completion latency percentiles (20 fields): |
| .RS |
| .B Xth percentile=usec |
| .RE |
| Total latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Bandwidth: |
| .RS |
| .B min, max, aggregate percentage of total, mean, standard deviation |
| .RE |
| .RE |
| .P |
| Write status: |
| .RS |
| .B Total I/O \fR(KB)\fP, bandwidth \fR(KB/s)\fP, IOPS, runtime \fR(ms)\fP |
| .P |
| Submission latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Completion latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Completion latency percentiles (20 fields): |
| .RS |
| .B Xth percentile=usec |
| .RE |
| Total latency: |
| .RS |
| .B min, max, mean, standard deviation |
| .RE |
| Bandwidth: |
| .RS |
| .B min, max, aggregate percentage of total, mean, standard deviation |
| .RE |
| .RE |
| .P |
| CPU usage: |
| .RS |
| .B user, system, context switches, major page faults, minor page faults |
| .RE |
| .P |
| IO depth distribution: |
| .RS |
| .B <=1, 2, 4, 8, 16, 32, >=64 |
| .RE |
| .P |
| IO latency distribution: |
| .RS |
| Microseconds: |
| .RS |
| .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000 |
| .RE |
| Milliseconds: |
| .RS |
| .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000 |
| .RE |
| .RE |
| .P |
| Disk utilization (1 for each disk used): |
| .RS |
| .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 |
| .RE |
| .P |
| Error Info (dependent on continue_on_error, default off): |
| .RS |
| .B total # errors, first error code |
| .RE |
| .P |
| .B text description (if provided in config - appears on newline) |
| .RE |
| .SH CLIENT / SERVER |
| Normally you would run fio as a stand-alone application on the machine |
| where the IO workload should be generated. However, it is also possible to |
| run the frontend and backend of fio separately. This makes it possible to |
| have a fio server running on the machine(s) where the IO workload should |
| be running, while controlling it from another machine. |
| |
| To start the server, you would do: |
| |
| \fBfio \-\-server=args\fR |
| |
| on that machine, where args defines what fio listens to. The arguments |
| are of the form 'type:hostname or IP:port'. 'type' is either 'ip' (or ip4) |
| for TCP/IP v4, 'ip6' for TCP/IP v6, or 'sock' for a local unix domain |
| socket. 'hostname' is either a hostname or IP address, and 'port' is the port to |
| listen to (only valid for TCP/IP, not a local socket). Some examples: |
| |
| 1) fio \-\-server |
| |
| Start a fio server, listening on all interfaces on the default port (8765). |
| |
| 2) fio \-\-server=ip:hostname,4444 |
| |
| Start a fio server, listening on IP belonging to hostname and on port 4444. |
| |
| 3) fio \-\-server=ip6:::1,4444 |
| |
| Start a fio server, listening on IPv6 localhost ::1 and on port 4444. |
| |
| 4) fio \-\-server=,4444 |
| |
| Start a fio server, listening on all interfaces on port 4444. |
| |
| 5) fio \-\-server=1.2.3.4 |
| |
| Start a fio server, listening on IP 1.2.3.4 on the default port. |
| |
| 6) fio \-\-server=sock:/tmp/fio.sock |
| |
| Start a fio server, listening on the local socket /tmp/fio.sock. |
| |
| When a server is running, you can connect to it from a client. The client |
| is run with: |
| |
| fio \-\-local-args \-\-client=server \-\-remote-args <job file(s)> |
| |
| where \-\-local-args are arguments that are local to the client where it is |
| running, 'server' is the connect string, and \-\-remote-args and <job file(s)> |
| are sent to the server. The 'server' string follows the same format as it |
| does on the server side, to allow IP/hostname/socket and port strings. |
| You can connect to multiple clients as well, to do that you could run: |
| |
| fio \-\-client=server2 \-\-client=server2 <job file(s)> |
| .SH AUTHORS |
| |
| .B fio |
| was written by Jens Axboe <jens.axboe@oracle.com>, |
| now Jens Axboe <jaxboe@fusionio.com>. |
| .br |
| This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based |
| on documentation by Jens Axboe. |
| .SH "REPORTING BUGS" |
| Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>. |
| See \fBREADME\fR. |
| .SH "SEE ALSO" |
| For further documentation see \fBHOWTO\fR and \fBREADME\fR. |
| .br |
| Sample jobfiles are available in the \fBexamples\fR directory. |
| |