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 "".
nrfiles=int Number of files to use for this job. Defaults to 1.
channel semantics (Send/Recv) for the
InfiniBand, RoCE and iWARP protocols.
- falloc IO engine that does regular fallocate to
- simulate data transfer as fio ioengine.
- DDIR_READ does fallocate(,mode = keep_size,)
- DDIR_WRITE does fallocate(,mode = 0)
- DDIR_TRIM does fallocate(,mode = punch_hole)
+ falloc IO engine that does regular fallocate to
+ simulate data transfer as fio ioengine.
+ DDIR_READ does fallocate(,mode = keep_size,)
+ DDIR_WRITE does fallocate(,mode = 0)
+ DDIR_TRIM does fallocate(,mode = punch_hole)
e4defrag IO engine that does regular EXT4_IOC_MOVE_EXT
- ioctls to simulate defragment activity in
- request to DDIR_WRITE event
+ ioctls to simulate defragment activity in
+ request to DDIR_WRITE event
+
+ rbd IO engine supporting direct access to Ceph
+ Rados Block Devices (RBD) via librbd without
+ the need to use the kernel rbd driver. This
+ ioengine defines engine specific options.
+
+ gfapi Using Glusterfs libgfapi sync interface to
+ direct access to Glusterfs volumes without
+ options.
+
+ gfapi_async Using Glusterfs libgfapi async interface
+ to direct access to Glusterfs volumes without
+ having to go through FUSE. This ioengine
+ defines engine specific options.
+
+ 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
caps the file size at real_size - offset.
offset_increment=int If this is provided, then the real offset becomes
- the offset + offset_increment * thread_number, where the
- thread number is a counter that starts at 0 and is incremented
- for each job. This option is useful if there are several jobs
- which are intended to operate on a file in parallel in disjoint
- segments, with even spacing between the starting points.
+ offset + offset_increment * thread_number, where the thread
+ number is a counter that starts at 0 and is incremented for
+ each sub-job (i.e. when numjobs option is specified). This
+ option is useful if there are several jobs which are intended
+ to operate on a file in parallel disjoint segments, with
+ even spacing between the starting points.
number_ios=int Fio will normally perform IOs until it has exhausted the size
of the region set by size=, or if it exhaust the allocated
jobs in their lifetime. The included fio_generate_plots
script uses gnuplot to turn these text files into nice
graphs. See write_lat_log for behaviour of given
- filename. For this option, the suffix is _bw.log.
+ filename. For this option, the suffix is _bw.x.log, where
+ x is the index of the job (1..N, where N is the number of
+ jobs).
write_lat_log=str Same as write_bw_log, except that this option stores io
submission, completion, and total latencies instead. If no
write_lat_log=foo
- The actual log names will be foo_slat.log, foo_clat.log,
- and foo_lat.log. This helps fio_generate_plot fine the logs
- automatically.
+ The actual log names will be foo_slat.x.log, foo_clat.x.log,
+ and foo_lat.x.log, where x is the index of the job (1..N,
+ where N is the number of jobs). This helps fio_generate_plot
+ fine the logs automatically.
write_iops_log=str Same as write_bw_log, but writes IOPS. If no filename is
given with this option, the default filename of
- "jobname_type.log" is used. Even if the filename is given,
- fio will still append the type of log.
+ "jobname_type.x.log" is used,where x is the index of the job
+ (1..N, where N is the number of jobs). Even if the filename
+ is given, fio will still append the type of log.
log_avg_msec=int By default, fio will log an entry in the iops, latency,
or bw log for every IO that completes. When writing to the
log_offset=int If this is set, the iolog options will include the byte
offset for the IO entry as well as the other data values.
+log_compression=int If this is set, fio will compress the IO logs as
+ it goes, to keep the memory footprint lower. When a log
+ reaches the specified size, that chunk is removed and
+ compressed in the background. Given that IO logs are
+ fairly highly compressible, this yields a nice memory
+ savings for longer runs. The downside is that the
+ compression will consume some background CPU cycles, so
+ it may impact the run. This, however, is also true if
+ the logging ends up consuming most of the system memory.
+ So pick your poison. The IO logs are saved normally at the
+ end of a run, by decompressing the chunks and storing them
+ in the specified log file. This feature depends on the
+ availability of zlib.
+
+log_store_compressed=bool If set, and log_compression is also set,
+ fio will store the log files in a compressed format. They
+ can be decompressed with fio, using the --inflate-log
+ command line parameter. The files will be stored with a
+ .fz suffix.
+
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.
projects / fio.git / blobdiff