calls will be excluded from other uses. Fio will manually clear it from the
CPU mask of other jobs.
+.. option:: job_start_clock_id=int
+ The clock_id passed to the call to `clock_gettime` used to record job_start
+ in the `json` output format. Default is 0, or CLOCK_REALTIME.
+
Target file/device
~~~~~~~~~~~~~~~~~~
On Windows, disk devices are accessed as :file:`\\\\.\\PhysicalDrive0` for
the first device, :file:`\\\\.\\PhysicalDrive1` for the second etc.
- Note: Windows and FreeBSD prevent write access to areas
+ Note: Windows and FreeBSD (refer to geom(4)) prevent write access to areas
of the disk containing in-use data (e.g. filesystems).
The filename "`-`" is a reserved name, meaning *stdin* or *stdout*. Which
.. option:: max_open_zones=int
- A zone of a zoned block device is in the open state when it is partially
- written (i.e. not all sectors of the zone have been written). Zoned
- block devices may have a limit on the total number of zones that can
- be simultaneously in the open state, that is, the number of zones that
- can be written to simultaneously. The :option:`max_open_zones` parameter
- limits the number of zones to which write commands are issued by all fio
- jobs, that is, limits the number of zones that will be in the open
- state. This parameter is relevant only if the :option:`zonemode` =zbd is
- used. The default value is always equal to maximum number of open zones
- of the target zoned block device and a value higher than this limit
- cannot be specified by users unless the option
- :option:`ignore_zone_limits` is specified. When
- :option:`ignore_zone_limits` is specified or the target device has no
- limit on the number of zones that can be in an open state,
- :option:`max_open_zones` can specify 0 to disable any limit on the
- number of zones that can be simultaneously written to by all jobs.
+ When a zone of a zoned block device is partially written (i.e. not all
+ sectors of the zone have been written), the zone is in one of three
+ conditions: 'implicit open', 'explicit open' or 'closed'. Zoned block
+ devices may have a limit called 'max_open_zones' (same name as the
+ parameter) on the total number of zones that can simultaneously be in
+ the 'implicit open' or 'explicit open' conditions. Zoned block devices
+ may have another limit called 'max_active_zones', on the total number of
+ zones that can simultaneously be in the three conditions. The
+ :option:`max_open_zones` parameter limits the number of zones to which
+ write commands are issued by all fio jobs, that is, limits the number of
+ zones that will be in the conditions. When the device has the
+ max_open_zones limit and does not have the max_active_zones limit, the
+ :option:`max_open_zones` parameter limits the number of zones in the two
+ open conditions up to the limit. In this case, fio includes zones in the
+ two open conditions to the write target zones at fio start. When the
+ device has both the max_open_zones and the max_active_zones limits, the
+ :option:`max_open_zones` parameter limits the number of zones in the
+ three conditions up to the limit. In this case, fio includes zones in
+ the three conditions to the write target zones at fio start.
+
+ This parameter is relevant only if the :option:`zonemode` =zbd is used.
+ The default value is always equal to the max_open_zones limit of the
+ target zoned block device and a value higher than this limit cannot be
+ specified by users unless the option :option:`ignore_zone_limits` is
+ specified. When :option:`ignore_zone_limits` is specified or the target
+ device does not have the max_open_zones limit, :option:`max_open_zones`
+ can specify 0 to disable any limit on the number of zones that can be
+ simultaneously written to by all jobs.
.. option:: job_max_open_zones=int
reads and writes. See :manpage:`ionice(1)`. See also the
:option:`prioclass` option.
+.. option:: cmdprio_hint=int[,int] : [io_uring] [libaio]
+
+ Set the I/O priority hint to use for I/Os that must be issued with
+ a priority when :option:`cmdprio_percentage` or
+ :option:`cmdprio_bssplit` is set. If not specified when
+ :option:`cmdprio_percentage` or :option:`cmdprio_bssplit` is set,
+ this defaults to 0 (no hint). A single value applies to reads and
+ writes. Comma-separated values may be specified for reads and writes.
+ See also the :option:`priohint` option.
+
.. option:: cmdprio=int[,int] : [io_uring] [libaio]
Set the I/O priority value to use for I/Os that must be issued with
cmdprio_bssplit=blocksize/percentage:blocksize/percentage
- In this case, each entry will use the priority class and priority
- level defined by the options :option:`cmdprio_class` and
- :option:`cmdprio` respectively.
+ In this case, each entry will use the priority class, priority hint
+ and priority level defined by the options :option:`cmdprio_class`,
+ :option:`cmdprio` and :option:`cmdprio_hint` respectively.
The second accepted format for this option is:
accepted format does not restrict all entries to have the same priority
class and priority level.
- For both formats, only the read and write data directions are supported,
+ The third accepted format for this option is:
+
+ cmdprio_bssplit=blocksize/percentage/class/level/hint:...
+
+ This is an extension of the second accepted format that allows one to
+ also specify a priority hint.
+
+ For all formats, only the read and write data directions are supported,
values for trim IOs are ignored. This option is mutually exclusive with
the :option:`cmdprio_percentage` option.
For direct I/O, requests will only succeed if cache invalidation isn't required,
file blocks are fully allocated and the disk request could be issued immediately.
-.. option:: fdp=bool : [io_uring_cmd]
+.. option:: fdp=bool : [io_uring_cmd] [xnvme]
Enable Flexible Data Placement mode for write commands.
-.. option:: fdp_pli=str : [io_uring_cmd]
+.. option:: fdp_pli_select=str : [io_uring_cmd] [xnvme]
+
+ Defines how fio decides which placement ID to use next. The following
+ types are defined:
+
+ **random**
+ Choose a placement ID at random (uniform).
+
+ **roundrobin**
+ Round robin over available placement IDs. This is the
+ default.
+
+ The available placement ID index/indices is defined by the option
+ :option:`fdp_pli`.
+
+.. option:: fdp_pli=str : [io_uring_cmd] [xnvme]
Select which Placement ID Index/Indicies this job is allowed to use for
writes. By default, the job will cycle through all available Placement
want fio to use placement identifier only at indices 0, 2 and 5 specify
``fdp_pli=0,2,5``.
+.. option:: md_per_io_size=int : [io_uring_cmd]
+
+ Size in bytes for separate metadata buffer per IO. Default: 0.
+
+.. option:: pi_act=int : [io_uring_cmd]
+
+ Action to take when nvme namespace is formatted with protection
+ information. If this is set to 1 and namespace is formatted with
+ metadata size equal to protection information size, fio won't use
+ separate metadata buffer or extended logical block. If this is set to
+ 1 and namespace is formatted with metadata size greater than protection
+ information size, fio will not generate or verify the protection
+ information portion of metadata for write or read case respectively.
+ If this is set to 0, fio generates protection information for
+ write case and verifies for read case. Default: 1.
+
+ For 16 bit CRC generation fio will use isa-l if available otherwise
+ it will use the default slower generator.
+ (see: https://github.com/intel/isa-l)
+
+.. option:: pi_chk=str[,str][,str] : [io_uring_cmd]
+
+ Controls the protection information check. This can take one or more
+ of these values. Default: none.
+
+ **GUARD**
+ Enables protection information checking of guard field.
+ **REFTAG**
+ Enables protection information checking of logical block
+ reference tag field.
+ **APPTAG**
+ Enables protection information checking of application tag field.
+
+.. option:: apptag=int : [io_uring_cmd]
+
+ Specifies logical block application tag value, if namespace is
+ formatted to use end to end protection information. Default: 0x1234.
+
+.. option:: apptag_mask=int : [io_uring_cmd]
+
+ Specifies logical block application tag mask value, if namespace is
+ formatted to use end to end protection information. Default: 0xffff.
+
.. option:: cpuload=int : [cpuio]
Attempt to use the specified percentage of CPU cycles. This is a mandatory
**hugepage**
Use hugepages, instead of existing posix memory backend. The
memory backend uses hugetlbfs. This require users to allocate
- hugepages, mount hugetlbfs and set an enviornment variable for
+ hugepages, mount hugetlbfs and set an environment variable for
XNVME_HUGETLB_PATH.
**spdk**
Uses SPDK's memory allocator.
creating but before connecting the libblkio instance. Each property must
have the format ``<name>=<value>``. Colons can be escaped as ``\:``.
These are set after the engine sets any other properties, so those can
- be overriden. Available properties depend on the libblkio version in use
+ be overridden. Available properties depend on the libblkio version in use
and are listed at
https://libblkio.gitlab.io/libblkio/blkio.html#properties
connecting but before starting the libblkio instance. Each property must
have the format ``<name>=<value>``. Colons can be escaped as ``\:``.
These are set after the engine sets any other properties, so those can
- be overriden. Available properties depend on the libblkio version in use
+ be overridden. Available properties depend on the libblkio version in use
and are listed at
https://libblkio.gitlab.io/libblkio/blkio.html#properties
I/O rate
~~~~~~~~
+.. option:: thinkcycles=int
+
+ Stall the job for the specified number of cycles after an I/O has completed before
+ issuing the next. May be used to simulate processing being done by an application.
+ This is not taken into account for the time to be waited on for :option:`thinktime`.
+ Might not have any effect on some platforms, this can be checked by trying a setting
+ a high enough amount of thinkcycles.
+
.. option:: thinktime=time
Stall the job for the specified period of time after an I/O has completed before issuing the
priority setting, see I/O engine specific :option:`cmdprio_percentage`
and :option:`cmdprio_class` options.
+.. option:: priohint=int
+
+ Set the I/O priority hint. This is only applicable to platforms that
+ support I/O priority classes and to devices with features controlled
+ through priority hints, e.g. block devices supporting command duration
+ limits, or CDL. CDL is a way to indicate the desired maximum latency
+ of I/Os so that the device can optimize its internal command scheduling
+ according to the latency limits indicated by the user.
+
+ For per-I/O priority hint setting, see the I/O engine specific
+ :option:`cmdprio_hint` option.
+
.. option:: cpus_allowed=str
Controls the same options as :option:`cpumask`, but accepts a textual
By default, fio will continue running all other jobs when one job finishes.
Sometimes this is not the desired action. Setting ``exitall`` will
instead make fio terminate all jobs in the same group. The option
- ``exit_what`` allows to control which jobs get terminated when ``exitall`` is
- enabled. The default is ``group`` and does not change the behaviour of
+ ``exit_what`` allows one to control which jobs get terminated when ``exitall``
+ is enabled. The default is ``group`` and does not change the behaviour of
``exitall``. The setting ``all`` terminates all jobs. The setting ``stonewall``
terminates all currently running jobs across all groups and continues execution
with the next stonewalled group.
.. option:: per_job_logs=bool
- If set, this generates bw/clat/iops log with per file private filenames. If
- not set, jobs with identical names will share the log filename. Default:
- true.
+ If set to true, fio generates bw/clat/iops logs with per job unique
+ filenames. If set to false, jobs with identical names will share a log
+ filename. Note that when this option is set to false log files will be
+ opened in append mode and if log files already exist the previous
+ contents will not be overwritten. Default: true.
.. option:: group_reporting
same reporting group, unless if separated by a :option:`stonewall`, or by
using :option:`new_group`.
+ NOTE: When :option:`group_reporting` is used along with `json` output,
+ there are certain per-job properties which can be different between jobs
+ but do not have a natural group-level equivalent. Examples include
+ `kb_base`, `unit_base`, `sig_figs`, `thread_number`, `pid`, and
+ `job_start`. For these properties, the values for the first job are
+ recorded for the group.
+
.. option:: new_group
Start a new reporting group. See: :option:`group_reporting`. If not given,
.. option:: log_unix_epoch=bool
- If set, fio will log Unix timestamps to the log files produced by enabling
- write_type_log for each log type, instead of the default zero-based
- timestamps.
+ Backwards compatible alias for log_alternate_epoch.
.. option:: log_alternate_epoch=bool
.. option:: log_alternate_epoch_clock_id=int
- Specifies the clock_id to be used by clock_gettime to obtain the alternate epoch
- if either log_unix_epoch or log_alternate_epoch are true. Otherwise has no
- effect. Default value is 0, or CLOCK_REALTIME.
+ Specifies the clock_id to be used by clock_gettime to obtain the alternate
+ epoch if log_alternate_epoch is true. Otherwise has no effect. Default
+ value is 0, or CLOCK_REALTIME.
.. option:: block_error_percentiles=bool
And finally, the disk statistics are printed. This is Linux specific. They will look like this::
Disk stats (read/write):
- sda: ios=16398/16511, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00%
+ sda: ios=16398/16511, sectors=32321/65472, merge=30/162, ticks=6853/819634, in_queue=826487, util=100.00%
Each value is printed for both reads and writes, with reads first. The
numbers denote:
**ios**
Number of I/Os performed by all groups.
+**sectors**
+ Amount of data transferred in units of 512 bytes for all groups.
**merge**
Number of merges performed by the I/O scheduler.
**ticks**
server. The `server` string follows the same format as it does on the server
side, to allow IP/hostname/socket and port strings.
+Note that all job options must be defined in job files when running fio as a
+client. Any job options specified in `remote-args` will be ignored.
+
Fio can connect to multiple servers this way::
fio --client=<server1> <job file(s)> --client=<server2> <job file(s)>