of those files. Internally that is the same as using the 'stonewall'
parameter described the the parameter section.
+If the job file contains only one job, you may as well just give the
+parameters on the command line. The command line parameters are identical
+to the job parameters, with a few extra that control global parameters
+(see README). For example, for the job file parameter iodepth=2, the
+mirror command line option would be --iodepth 2 or --iodepth=2. You can
+also use the command line for giving more than one job entry. For each
+--name option that fio sees, it will start a new job with that name.
+Command line entries following a --name entry will apply to that job,
+until there are no more entries or a new --name entry is seen. This is
+similar to the job file options, where each option applies to the current
+job until a new [] job entry is seen.
+
fio does not need to run as root, except if the files or devices specified
in the job section requires that. Some other options may also be restricted,
such as memory locking, io scheduler switching, and descreasing the nice value.
As you can see, the job file sections themselves are empty as all the
described parameters are shared. As no filename= option is given, fio
-makes up a filename for each of the jobs as it sees fit.
+makes up a filename for each of the jobs as it sees fit. On the command
+line, this job would look as follows:
+
+$ fio --name=global --rw=randread --size=128m --name=job1 --name=job2
+
Lets look at an example that have a number of processes writing randomly
to files.
We want to use async io here, with a depth of 4 for each file. We also
increased the buffer size used to 32KiB and define numjobs to 4 to
fork 4 identical jobs. The result is 4 processes each randomly writing
-to their own 64MiB file.
+to their own 64MiB file. Instead of using the above job file, you could
+have given the parameters on the command line. For this case, you would
+specify:
+
+$ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
fio ships with a few example job files, you can also look there for
inspiration.
name=str ASCII name of the job. This may be used to override the
name printed by fio for this job. Otherwise the job
- name is used.
+ name is used. On the command line this parameter has the
+ special purpose of also signalling the start of a new
+ job.
directory=str Prefix filenames with this directory. Used to places files
in a different location than "./".
bs=siint The block size used for the io units. Defaults to 4k.
+read_bs=siint
+write_bs=siint If the workload is a mixed read-write workload, you can use
+ these options to set seperate block sizes.
+
bsrange=irange Instead of giving a single block size, specify a range
and fio will mix the issued io block sizes. The issued
io unit will always be a multiple of the minimum value
- given.
+ given (also see bs_unaligned).
+
+read_bsrange=irange
+write_bsrange=irange
+ If the workload is a mixed read-write workload, you can use
+ one of these options to set separate block size ranges for
+ reads and writes.
+
+bs_unaligned If this option is given, any byte size value within bsrange
+ may be used as a block range. This typically wont work with
+ direct IO, as that normally requires sector alignment.
nrfiles=int Number of files to use for this job. Defaults to 1.
up to 100%, the latter of the two will be used to override
the first.
+norandommap Normally fio will cover every block of the file when doing
+ random IO. If this option is given, fio will just get a
+ new random offset without looking at past io history. This
+ means that some blocks may not be read or written, and that
+ some blocks may be read/written more than once. This option
+ is mutually exclusive with verify= for that reason.
+
nice=int Run the job with the given nice value. See man nice(2).
prio=int Set the io priority value of this job. Linux limits us to
fio spits out a lot of output. While running, fio will display the
status of the jobs created. An example of that would be:
-Threads running: 1: [_r] [24.79% done] [eta 00h:01m:31s]
+Threads running: 1: [_r] [24.79% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
The characters inside the square brackets denote the current status of
each thread. The possible values (in typical life cycle order) are:
_ Thread reaped.
The other values are fairly self explanatory - number of threads
-currently running and doing io, and the estimated completion percentage
-and time for the running group. It's impossible to estimate runtime
-of the following groups (if any).
+currently running and doing io, rate of io since last check, and the estimated
+completion percentage and time for the running group. It's impossible to
+estimate runtime of the following groups (if any).
When fio is done (or interrupted by ctrl-c), it will show the data for
each thread, group of threads, and disks in that order. For each data
projects / fio.git / blobdiff