fio --- fio is a tool that will spawn a number of threads or processes doing a particular type of io action as specified by the user. fio takes a number of global parameters, each inherited by the thread unless otherwise parameters given to them overriding that setting is given. The typical use of fio is to write a job file matching the io load one wants to simulate. Source ------ fio resides in a git repo, the canonical place is: git://git.kernel.dk/data/git/fio.git The http protocol also works, path is the same. Snapshots are frequently generated and they include the git meta data as well. You can download them here: http://brick.kernel.dk/snaps/ Pascal Bleser has fio RPMs in his repository for SUSE variants, you can find them here: http://linux01.gwdg.de/~pbleser/rpm-navigation.php?cat=System/fio Dag Wieƫrs has RPMs for Red Hat related distros, find them here: http://dag.wieers.com/rpm/packages/fio/ Mailing list ------------ There's a mailing list associated with fio. It's meant for general discussion, bug reporting, questions - basically anything that has to do with fio. An automated mail detailing recent commits is automatically sent to the list at most daily. The list address is fio-devel@kernel.dk, subscribe by sending an empty email to fio-devel+subscribe@kernel.dk. Building -------- Just type 'make' and 'make install'. If on FreeBSD, for now you have to specify the FreeBSD Makefile with -f, eg: $ make -f Makefile.Freebsd && make -f Makefile.FreeBSD install Likewise with OpenSolaris, use the Makefile.solaris to compile there. This might change in the future if I opt for an autoconf type setup. Command line ------------ $ fio --output Write output to file --runtime Runtime in seconds --latency-log Generate per-job latency logs --bandwidth-log Generate per-job bandwidth logs --minimal Minimal (terse) output --version Print version info and exit --help Print this page --cmdhelp=cmd Print command help, "all" for all of them --showcmd Turn a job file into command line options Any parameters following the options will be assumed to be job files, unless they match a job file parameter. You can add as many as you want, each job file will be regarded as a separate group and fio will stonewall its execution. Job file -------- See the HOWTO file for a more detailed description of parameters and what they mean. This file contains the terse version. Only a few options can be controlled with command line parameters, generally it's a lot easier to just write a simple job file to describe the workload. The job file format is in the ini style format, as it's easy to read and write for the user. The job file parameters are: name=x Use 'x' as the identifier for this job. description=x 'x' is a text description of the job. directory=x Use 'x' as the top level directory for storing files filename=x Force the use of 'x' as the filename for all files in this thread. If not given, fio will make up a suitable filename based on the thread and file number. rw=x 'x' may be: read, randread, write, randwrite, rw (read-write mix), randrw (read-write random mix) rwmixcycle=x Base cycle for switching between read and write in msecs. rwmixread=x 'x' percentage of rw mix ios will be reads. If rwmixwrite is also given, the last of the two will be used if they don't add up to 100%. rwmixwrite=x 'x' percentage of rw mix ios will be writes. See rwmixread. rand_repeatable=x The sequence of random io blocks can be repeatable across runs, if 'x' is 1. size=x Set file size to x bytes (x string can include k/m/g) ioengine=x 'x' may be: aio/libaio/linuxaio for Linux aio, posixaio for POSIX aio, sync for regular read/write io, mmap for mmap'ed io, syslet-rw for syslet driven read/write, splice for using splice/vmsplice, sgio for direct SG_IO io, net for network io, or cpuio for a cycler burner load. sgio only works on Linux on SCSI (or SCSI-like devices, such as usb-storage or sata/libata driven) devices. Fio also has a null io engine, which is mainly used for testing fio itself. iodepth=x For async io, allow 'x' ios in flight overwrite=x If 'x', layout a write file first. nrfiles=x Spread io load over 'x' number of files per job, if possible. prio=x Run io at prio X, 0-7 is the kernel allowed range prioclass=x Run io at prio class X bs=x Use 'x' for thread blocksize. May include k/m postfix. bsrange=x-y Mix thread block sizes randomly between x and y. May also include k/m postfix. direct=x 1 for direct IO, 0 for buffered IO thinktime=x "Think" x usec after each io rate=x Throttle rate to x KiB/sec ratemin=x Quit if rate of x KiB/sec can't be met ratecycle=x ratemin averaged over x msecs cpumask=x Only allow job to run on CPUs defined by mask. fsync=x If writing with buffered IO, fsync after every 'x' blocks have been written. end_fsync=x If 'x', run fsync() after end-of-job. startdelay=x Start this thread x seconds after startup runtime=x Terminate x seconds after startup. Can include a normal time suffix if not given in seconds, such as 'm' for minutes, 'h' for hours, and 'd' for days. offset=x Start io at offset x (x string can include k/m/g) invalidate=x Invalidate page cache for file prior to doing io sync=x Use sync writes if x and writing buffered IO. mem=x If x == malloc, use malloc for buffers. If x == shm, use shared memory for buffers. If x == mmap, use anonymous mmap. exitall When one thread quits, terminate the others bwavgtime=x Average bandwidth stats over an x msec window. create_serialize=x If 'x', serialize file creation. create_fsync=x If 'x', run fsync() after file creation. unlink If set, unlink files when done. loops=x Run the job 'x' number of times. verify=x If 'x' == md5, use md5 for verifies. If 'x' == crc32, use crc32 for verifies. md5 is 'safer', but crc32 is a lot faster. Only makes sense for writing to a file. stonewall Wait for preceeding jobs to end before running. numjobs=x Create 'x' similar entries for this job thread Use pthreads instead of forked jobs zonesize=x zoneskip=y Zone options must be paired. If given, the job will skip y bytes for every x read/written. This can be used to gauge hard drive speed over the entire platter, without reading everything. Both x/y can include k/m/g suffix. iolog=x Open and read io pattern from file 'x'. The file must contain one io action per line in the following format: rw, offset, length where with rw=0/1 for read/write, and the offset and length entries being in bytes. write_iolog=x Write an iolog to file 'x' in the same format as iolog. The iolog options are exclusive, if both given the read iolog will be performed. write_bw_log Write a bandwidth log. write_lat_log Write a latency log. lockmem=x Lock down x amount of memory on the machine, to simulate a machine with less memory available. x can include k/m/g suffix. nice=x Run job at given nice value. exec_prerun=x Run 'x' before job io is begun. exec_postrun=x Run 'x' after job io has finished. ioscheduler=x Use ioscheduler 'x' for this job. cpuload=x For a CPU io thread, percentage of CPU time to attempt to burn. cpuchunks=x Split burn cycles into pieces of x usecs. Author ------ Fio was written by Jens Axboe to enable flexible testing of the Linux IO subsystem and schedulers. He got tired of writing specific test applications to simulate a given workload, and found that the existing io benchmark/test tools out there weren't flexible enough to do what he wanted. Jens Axboe 20060905