-See the HOWTO file for a more detailed description of parameters and what
-they mean. This file contains the terse version. You can describe big and
-complex setups with the command line, but 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 that is 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, solarisaio for Solaris
- native async IO, windowsaio for Windows native async IO,
- sync for regular read/write io,
- psync for regular pread/pwrite io, vsync for regular
- readv/writev (with queuing emulation) mmap for mmap'ed
- io, syslet-rw for syslet driven read/write, splice for
- using splice/vmsplice, sg for direct SG_IO io, net
- for network io, or cpuio for a cycler burner load. sg
- 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 KB/sec
- ratemin=x Quit if rate of x KB/sec can't be met
- ratecycle=x ratemin averaged over x msecs
- cpumask=x Only allow job to run on CPUs defined by mask.
- cpus_allowed=x Like 'cpumask', but allow text setting of CPU affinity.
- 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.
- For other types of checksumming, see HOWTO.
- 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. Specify a separate file
- for each job, otherwise the iologs will be interspersed
- and the file may be corrupt.
- 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.
+See the HOWTO file for a complete description of job file syntax and
+parameters. The --cmdhelp option also lists all options. If used with
+an option argument, --cmdhelp will detail the given option. The job file
+format is in the ini style format, as that is easy for the user to review
+and modify.
+
+This README contains the terse version. Job files can describe big and
+complex setups that are not possible with the command line. Job files
+are a good practice even for simple jobs since the file provides an
+easily accessed record of the workload and can include comments.
+
+See the examples/ directory for inspiration on how to write job files. Note
+the copyright and license requirements currently apply to examples/ files.
+
+
+Client/server
+------------
+
+Normally fio is invoked as a stand-alone application on the machine
+where the IO workload should be generated. However, the frontend and
+backend of fio can be run separately. Ie the fio server can generate
+an IO workload on the "Device Under Test" while being controlled from
+another machine.
+
+Start the server on the machine which has access to the storage DUT:
+
+fio --server=args
+
+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.
+
+Once a server is running, a "client" can connect to the fio server with:
+
+fio --local-args --client=<server> --remote-args <job file(s)>
+
+where --local-args are arguments for 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.
+
+Fio can connect to multiple servers this way:
projects / fio.git / blobdiff