If the option accepts an upper and lower range, use a colon ':' or
minus '-' to separate such values. See :ref:`irange <irange>`.
+ If the lower value specified happens to be larger than the upper value,
+ two values are swapped.
.. _bool:
If this isn't set, fio will abort jobs that are destructive (e.g. that write)
to what appears to be a mounted device or partition. This should help catch
creating inadvertently destructive tests, not realizing that the test will
- destroy data on the mounted file system. Default: false.
+ destroy data on the mounted file system. Note that some platforms don't allow
+ writing against a mounted device regardless of this option. Default: false.
.. option:: pre_read=bool
blocks given. For example, if you give 32 as a parameter, fio will sync the
file for every 32 writes issued. If fio is using non-buffered I/O, we may
not sync the file. The exception is the sg I/O engine, which synchronizes
- the disk cache anyway.
+ the disk cache anyway. Defaults to 0, which means no sync every certain
+ number of writes.
.. option:: fdatasync=int
Like :option:`fsync` but uses :manpage:`fdatasync(2)` to only sync data and
not metadata blocks. In Windows, FreeBSD, and DragonFlyBSD there is no
:manpage:`fdatasync(2)`, this falls back to using :manpage:`fsync(2)`.
+ Defaults to 0, which means no sync data every certain number of writes.
.. option:: write_barrier=int
**sync**
Basic :manpage:`read(2)` or :manpage:`write(2)`
I/O. :manpage:`lseek(2)` is used to position the I/O location.
+ See :option:`fsync` and :option:`fdatasync` for syncing write I/Os.
**psync**
Basic :manpage:`pread(2)` or :manpage:`pwrite(2)` I/O. Default on
.. option:: cpuload=int : [cpuio]
- Attempt to use the specified percentage of CPU cycles.
+ Attempt to use the specified percentage of CPU cycles. This is a mandatory
+ option when using cpuio I/O engine.
.. option:: cpuchunks=int : [cpuio]
all jobs in a file will be part of the same reporting group, unless
separated by a :option:`stonewall`.
+.. option:: stats
+
+ By default, fio collects and shows final output results for all jobs
+ that run. If this option is set to 0, then fio will ignore it in
+ the final stat output.
+
.. option:: write_bw_log=str
If given, write a bandwidth log for this job. Can be used to store data of