a string. The following types are used:
str String. This is a sequence of alpha characters.
-int Integer. A whole number value, can be negative. If prefixed with
- 0x, the integer is assumed to be of base 16 (hexadecimal).
time Integer with possible time postfix. In seconds unless otherwise
specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds,
minutes, and hours.
-siint SI integer. A whole number value, which may contain a postfix
+int SI integer. A whole number value, which may contain a postfix
describing the base of the number. Accepted postfixes are k/m/g,
meaning kilo, mega, and giga. So if you want to specify 4096,
you could either write out '4096' or just give 4k. The postfixes
as 1024-4096. A colon may also be used as the separator, eg
1k:4k. If the option allows two sets of ranges, they can be
specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see
- siint.
+ int.
With the above in mind, here follows the complete list of fio job
parameters.
If set, fio will use POSIX_FADV_SEQUENTIAL for sequential
IO and POSIX_FADV_RANDOM for random IO.
-size=siint The total size of file io for this job. Fio will run until
+size=int The total size of file io for this job. Fio will run until
this many bytes has been transferred, unless runtime is
limited by other options (such as 'runtime', for instance).
Unless specific nr_files and filesize options are given,
fio will divide this size between the available files
specified by the job.
-filesize=siint Individual file sizes. May be a range, in which case fio
+filesize=int Individual file sizes. May be a range, in which case fio
will select sizes for files at random within the given range
and limited to 'size' in total (if that is given). If not
given, each created file is the same size.
space left on device) as the terminating condition. Only makes
sense with sequential write.
-blocksize=siint
-bs=siint The block size used for the io units. Defaults to 4k. Values
- can be given for both read and writes. If a single siint is
- given, it will apply to both. If a second siint is specified
+blocksize=int
+bs=int The block size used for the io units. Defaults to 4k. Values
+ can be given for both read and writes. If a single int is
+ given, it will apply to both. If a second int is specified
after a comma, it will apply to writes only. In other words,
the format is either bs=read_and_write or bs=read,write.
bs=4k,8k will thus use 4k blocks for reads, and 8k blocks
can do so by passing an empty read size - bs=,8k will set
8k for writes and leave the read default value.
+blockalign=int
+ba=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.
+
blocksize_range=irange
bsrange=irange Instead of giving a single block size, specify a range
and fio will mix the issued io block sizes. The issued
always add up to 100, if bssplit is given a range that adds
up to more, it will error out.
+ bssplit also supports giving separate splits to reads and
+ writes. The format is identical to what bs= accepts. You
+ have to separate the read and write parts with a comma. So
+ if you want a workload that has 50% 2k reads and 50% 4k reads,
+ while having 90% 4k writes and 10% 8k writes, you would
+ specify:
+
+ bssplit=2k/50:4k/50,4k/90,8k/10
+
blocksize_unaligned
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
buffered=bool If value is true, use buffered io. This is the opposite
of the 'direct' option. Defaults to true.
-offset=siint Start io at the given offset in the file. The data before
+offset=int Start io at the given offset in the file. The data before
the given offset will not be touched. This effectively
caps the file size at real_size - offset.
location should point there. So if it's mounted in /huge,
you would use mem=mmaphuge:/huge/somefile.
-hugepage-size=siint
+hugepage-size=int
Defines the size of a huge page. Must at least be equal
to the system setting, see /proc/meminfo. Defaults to 4MiB.
Should probably always be a multiple of megabytes, so using
fast IO where the red-black tree sorting CPU time becomes
significant.
-verify_offset=siint Swap the verification header with data somewhere else
+verify_offset=int Swap the verification header with data somewhere else
in the block before writing. Its swapped back before
verifying.
-verify_interval=siint Write the verification header at a finer granularity
+verify_interval=int Write the verification header at a finer granularity
than the blocksize. It will be written for chunks the
size of header_interval. blocksize should divide this
evenly.
given, fio will use pthread_create(3) to create threads
instead.
-zonesize=siint Divide a file into zones of the specified size. See zoneskip.
+zonesize=int Divide a file into zones of the specified size. See zoneskip.
-zoneskip=siint Skip the specified number of bytes when zonesize data has
+zoneskip=int Skip the specified number of bytes when zonesize data has
been read. The two zone options can be used to only do
io on zones of a file.
The actual log names will be foo_clat.log and foo_slat.log.
This helps fio_generate_plot fine the logs automatically.
-lockmem=siint Pin down the specified amount of memory with mlock(2). Can
+lockmem=int Pin down the specified amount of memory with mlock(2). Can
potentially be used instead of removing memory or booting
with less memory to simulate a smaller amount of memory.