$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
+When fio is utilized as a basis of any reasonably large test suite, it might be
+desirable to share a set of standardized settings across multiple job files.
+Instead of copy/pasting such settings, any section may pull in an external
+.fio file with 'include filename' directive, as in the following example:
+
+; -- start job file including.fio --
+[global]
+filename=/tmp/test
+filesize=1m
+include glob-include.fio
+
+[test]
+rw=randread
+bs=4k
+time_based=1
+runtime=10
+include test-include.fio
+; -- end job file including.fio --
+
+; -- start job file glob-include.fio --
+thread=1
+group_reporting=1
+; -- end job file glob-include.fio --
+
+; -- start job file test-include.fio --
+ioengine=libaio
+iodepth=4
+; -- end job file test-include.fio --
+
+Settings pulled into a section apply to that section only (except global
+section). Include directives may be nested in that any included file may
+contain further include directive(s). Include files may not contain []
+sections.
+
+
4.1 Environment variables
-------------------------
This section describes in details each parameter associated with a job.
Some parameters take an option of a given type, such as an integer or
-a string. The following types are used:
+a string. Anywhere a numeric value is required, an arithmetic expression
+may be used, provided it is surrounded by parentheses. Supported operators
+are:
+
+ addition (+)
+ subtraction (-)
+ multiplication (*)
+ division (/)
+ modulus (%)
+ exponentiation (^)
+
+For time values in expressions, units are microseconds by default. This is
+different than for time values not in expressions (not enclosed in
+parentheses). The following types are used:
str String. This is a sequence of alpha characters.
time Integer with possible time suffix. In seconds unless otherwise
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
- one by appending a ':<nr>' to the end of the string given.
+ done by appending a ':<nr>' to the end of the string given.
For a random read, it would look like 'rw=randread:8' for
passing in an offset modifier with a value of 8. If the
suffix is used with a sequential IO pattern, then the value
If not set, the random sequence depends on the randrepeat
setting.
-use_os_rand=bool 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.
-
fallocate=str Whether pre-allocation is performed when laying down files.
Accepted values are:
while having 90% 4k writes and 10% 8k writes, you would
specify:
- bssplit=2k/50:4k/50,4k/90,8k/10
+ bssplit=2k/50:4k/50,4k/90:8k/10
blocksize_unaligned
bs_unaligned If this option is given, any byte size value within bsrange
alternate random and zeroed data throughout the IO
buffer.
-buffer_pattern=str If set, fio will fill the io buffers with this pattern.
- If not set, the contents of io buffers is defined by the other
- options related to buffer contents. The setting can be any
- pattern of bytes, and can be prefixed with 0x for hex values.
+buffer_pattern=str If set, fio will fill the io buffers with this
+ pattern. If not set, the contents of io buffers is defined by
+ the other options related to buffer contents. The setting can
+ be any pattern of bytes, and can be prefixed with 0x for hex
+ values. It may also be a string, where the string must then
+ be wrapped with "".
+
+dedupe_percentage=int If set, fio will generate this percentage of
+ identical buffers when writing. These buffers will be
+ naturally dedupable. The contents of the buffers depend on
+ what other buffer compression settings have been set. It's
+ possible to have the individual buffers either fully
+ compressible, or not at all. This option only controls the
+ distribution of unique buffers.
nrfiles=int Number of files to use for this job. Defaults to 1.
having to go through FUSE. This ioengine
defines engine specific options.
- hdfs Read and write through Hadoop (HDFS).
+ libhdfs Read and write through Hadoop (HDFS).
+ The 'filename' option is used to specify host,
+ port of the hdfs name-node to connect. This
+ engine interprets offsets a little
+ differently. In HDFS, files once created
+ cannot be modified. So random writes are not
+ possible. To imitate this, libhdfs engine
+ expects bunch of small files to be created
+ over HDFS, and engine will randomly pick a
+ file out of those files based on the offset
+ generated by fio backend. (see the example
+ job file to create such files, use rw=write
+ option). Please note, you might want to set
+ necessary environment variables to work with
+ hdfs/libhdfs properly.
external Prefix to specify loading an external
IO engine object file. Append the engine
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.
+ and report status. Note that this does not extend the amount
+ of IO that will be done, it will only stop fio if this
+ condition is met before other end-of-job criteria.
fsync=int If writing to a file, issue a sync of the dirty data
for every number of blocks given. For example, if you give
if verify_backlog_batch is larger than verify_backlog, some
blocks will be verified more than once.
+verify_state_save=bool When a job exits during the write phase of a verify
+ workload, save its current state. This allows fio to replay
+ up until that point, if the verify state is loaded for the
+ verify read phase. The format of the filename is, roughly,
+ <type>-<jobname>-<jobindex>-verify.state. <type> is "local"
+ for a local run, "sock" for a client/server socket connection,
+ and "ip" (192.168.0.1, for instance) for a networked
+ client/server connection.
+
+verify_state_load=bool If a verify termination trigger was used, fio stores
+ the current write state of each thread. This can be used at
+ verification time so that fio knows how far it should verify.
+ Without this information, fio will run a full verification
+ pass, according to the settings in the job file used.
+
stonewall
wait_for_previous Wait for preceding jobs in the job file to exit, before
starting this one. Can be used to insert serialization
address.
[netsplice] port=int
-[net] port=int The TCP or UDP port to bind to or connect to.
+[net] port=int The TCP or UDP port to bind to or connect to. If this is used
+with numjobs to spawn multiple instances of the same job type, then this will
+be the starting port number since fio will use a range of ports.
[netsplice] interface=str
[net] interface=str The IP address of the network interface used to send or
[net] 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.
+
[net] pingpong Normaly 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,
single reader when multiple readers are listening to the same
address.
+[net] window_size Set the desired socket buffer size for the connection.
+
+[net] mss Set the TCP maximum segment size (TCP_MAXSEG).
+
[e4defrag] donorname=str
File will be used as a block donor(swap extents between files)
[e4defrag] inplace=int
and standard deviation of time to complete an unit work is reported in "unit
work" section. Options can be chosen to report detailed percpu idleness or
overall system idleness by aggregating percpu stats.
+
+
+10.0 Verification and triggers
+------------------------------
+Fio is usually run in one of two ways, when data verification is done. The
+first is a normal write job of some sort with verify enabled. When the
+write phase has completed, fio switches to reads and verifies everything
+it wrote. The second model is running just the write phase, and then later
+on running the same job (but with reads instead of writes) to repeat the
+same IO patterns and verify the contents. Both of these methods depend
+on the write phase being completed, as fio otherwise has no idea how much
+data was written.
+
+With verification triggers, fio supports dumping the current write state
+to local files. Then a subsequent read verify workload can load this state
+and know exactly where to stop. This is useful for testing cases where
+power is cut to a server in a managed fashion, for instance.
+
+A verification trigger consists of two things:
+
+1) Storing the write state of each job
+2) Executing a trigger command
+
+The write state is relatively small, on the order of hundreds of bytes
+to single kilobytes. It contains information on the number of completions
+done, the last X completions, etc.
+
+A trigger is invoked either through creation ('touch') of a specified
+file in the system, or through a timeout setting. If fio is run with
+--trigger-file=/tmp/trigger-file, then it will continually check for
+the existence of /tmp/trigger-file. When it sees this file, it will
+fire off the trigger (thus saving state, and executing the trigger
+command).
+
+For client/server runs, there's both a local and remote trigger. If
+fio is running as a server backend, it will send the job states back
+to the client for safe storage, then execute the remote trigger, if
+specified. If a local trigger is specified, the server will still send
+back the write state, but the client will then execute the trigger.
+
+10.1 Verification trigger example
+---------------------------------
+Lets say we want to run a powercut test on the remote machine 'server'.
+Our write workload is in write-test.fio. We want to cut power to 'server'
+at some point during the run, and we'll run this test from the safety
+or our local machine, 'localbox'. On the server, we'll start the fio
+backend normally:
+
+server# fio --server
+
+and on the client, we'll fire off the workload:
+
+localbox$ fio --client=server --trigger-file=/tmp/my-trigger --trigger-remote="bash -c \"echo b > /proc/sysrq-triger\""
+
+We set /tmp/my-trigger as the trigger file, and we tell fio to execute
+
+echo b > /proc/sysrq-trigger
+
+on the server once it has received the trigger and sent us the write
+state. This will work, but it's not _really_ cutting power to the server,
+it's merely abruptly rebooting it. If we have a remote way of cutting
+power to the server through IPMI or similar, we could do that through
+a local trigger command instead. Lets assume we have a script that does
+IPMI reboot of a given hostname, ipmi-reboot. On localbox, we could
+then have run fio with a local trigger instead:
+
+localbox$ fio --client=server --trigger-file=/tmp/my-trigger --trigger="ipmi-reboot server"
+
+For this case, fio would wait for the server to send us the write state,
+then execute 'ipmi-reboot server' when that happened.
+
+10.1 Loading verify state
+-------------------------
+To load store write state, read verification job file must contain
+the verify_state_load option. If that is set, fio will load the previously
+stored state. For a local fio run this is done by loading the files directly,
+and on a client/server run, the server backend will ask the client to send
+the files over and load them from there.
projects / fio.git / blobdiff