-.TH fio 1 "October 2013" "User Manual"
+.TH fio 1 "December 2014" "User Manual"
.SH NAME
fio \- flexible I/O tester
.SH SYNOPSIS
.BI \-\-output \fR=\fPfilename
Write output to \fIfilename\fR.
.TP
+.BI \-\-output-format \fR=\fPformat
+Set the reporting format to \fInormal\fR, \fIterse\fR, or \fIjson\fR.
+.TP
.BI \-\-runtime \fR=\fPruntime
Limit run time to \fIruntime\fR seconds.
.TP
-.B \-\-latency\-log
-Generate per-job latency logs.
-.TP
.B \-\-bandwidth\-log
Generate per-job bandwidth logs.
.TP
Background a fio server, writing the pid to the given pid file.
.TP
.BI \-\-client \fR=\fPhost
-Instead of running the jobs locally, send and run them on the given host.
+Instead of running the jobs locally, send and run them on the given host or set of hosts. See client/server section.
.TP
.BI \-\-idle\-prof \fR=\fPoption
Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate).
.TP
.B randrw
Mixed random reads and writes.
+.TP
+.B trimwrite
+Trim and write mixed workload. Blocks will be trimmed first, then the same
+blocks will be written to.
.RE
.P
For mixed I/O, the default split is 50/50. For certain types of io the result
control what sequence of output is being generated. If not set, the random
sequence depends on the \fBrandrepeat\fR setting.
.TP
-.BI use_os_rand \fR=\fPbool
-Fio can either use the random generator supplied by the OS to generate random
-offsets, or it can use its own internal generator (based on Tausworthe).
-Default is to use the internal generator, which is often of better quality and
-faster. Default: false.
-.TP
.BI fallocate \fR=\fPstr
Whether pre-allocation is performed when laying down files. Accepted values
are:
Use \fBposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
are likely to be issued. Default: true.
.TP
+.BI fadvise_stream \fR=\fPint
+Use \fBposix_fadvise\fR\|(2) to advise the kernel what stream ID the
+writes issued belong to. Only supported on Linux. Note, this option
+may change going forward.
+.TP
.BI size \fR=\fPint
Total size of I/O for this job. \fBfio\fR will run until this many bytes have
-been transferred, unless limited by other options (\fBruntime\fR, for instance).
-Unless \fBnrfiles\fR and \fBfilesize\fR options are given, this amount will be
-divided between the available files for the job. If not set, fio will use the
-full size of the given files or devices. If the files do not exist, size
-must be given. It is also possible to give size as a percentage between 1 and
-100. If size=20% is given, fio will use 20% of the full size of the given
-files or devices.
-.TP
-.BI io_limit \fR=\fPint
+been transferred, unless limited by other options (\fBruntime\fR, for instance,
+or increased/descreased by \fBio_size\fR). Unless \fBnrfiles\fR and
+\fBfilesize\fR options are given, this amount will be divided between the
+available files for the job. If not set, fio will use the full size of the
+given files or devices. If the files do not exist, size must be given. It is
+also possible to give size as a percentage between 1 and 100. If size=20% is
+given, fio will use 20% of the full size of the given files or devices.
+.TP
+.BI io_size \fR=\fPint "\fR,\fB io_limit \fR=\fPint
Normally fio operates within the region set by \fBsize\fR, which means that
the \fBsize\fR option sets both the region and size of IO to be performed.
Sometimes that is not what you want. With this option, it is possible to
define just the amount of IO that fio should do. For instance, if \fBsize\fR
is set to 20G and \fBio_limit\fR is set to 5G, fio will perform IO within
-the first 20G but exit when 5G have been done.
+the first 20G but exit when 5G have been done. The opposite is also
+possible - if \fBsize\fR is set to 20G, and \fBio_size\fR is set to 40G, then
+fio will do 40G of IO within the 0..20G region.
.TP
.BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool
Sets size to something really large and waits for ENOSPC (no space left on
.TP
.B zero_buffers
Initialize buffers with all zeros. Default: fill buffers with random data.
-The resulting IO buffers will not be completely zeroed, unless
-\fPscramble_buffers\fR is also turned off.
.TP
.B refill_buffers
If this option is given, fio will refill the IO buffers on every submit. The
.BI buffer_compress_percentage \fR=\fPint
If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
that compress to the specified level. Fio does this by providing a mix of
-random data and zeroes. Note that this is per block size unit, for file/disk
-wide compression level that matches this setting, you'll also want to set
-\fBrefill_buffers\fR.
+random data and a fixed pattern. The fixed pattern is either zeroes, or the
+pattern specified by \fBbuffer_pattern\fR. If the pattern option is used, it
+might skew the compression ratio slightly. Note that this is per block size
+unit, for file/disk wide compression level that matches this setting. Note
+that this is per block size unit, for file/disk wide compression level that
+matches this setting, you'll also want to set refill_buffers.
.TP
.BI buffer_compress_chunk \fR=\fPint
See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how
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.
+.TP
+.B mtd
+Read, write and erase an MTD character device (e.g., /dev/mtd0). Discards are
+treated as erases. Depending on the underlying device type, the I/O may have
+to go in a certain pattern, e.g., on NAND, writing sequentially to erase blocks
+and discarding before overwriting. The writetrim mode works well for this
+constraint.
.RE
.P
.RE
Low watermark indicating when to start filling the queue again. Default:
\fBiodepth\fR.
.TP
+.BI io_submit_mode \fR=\fPstr
+This option controls how fio submits the IO to the IO engine. The default is
+\fBinline\fR, which means that the fio job threads submit and reap IO directly.
+If set to \fBoffload\fR, the job threads will offload IO submission to a
+dedicated pool of IO threads. This requires some coordination and thus has a
+bit of extra overhead, especially for lower queue depth IO where it can
+increase latencies. The benefit is that fio can manage submission rates
+independently of the device completion rates. This avoids skewed latency
+reporting if IO gets back up on the device side (the coordinated omission
+problem).
+.TP
.BI direct \fR=\fPbool
If true, use non-buffered I/O (usually O_DIRECT). Default: false.
.TP
.B lfsr
Linear feedback shift register generator
.TP
+.B tausworthe64
+Strong 64-bit 2^258 cycle random number generator
+.TP
.RE
.P
Tausworthe is a strong random number generator, but it requires tracking on the
.BI startdelay \fR=\fPirange
Delay start of job for the specified number of seconds. Supports all time
suffixes to allow specification of hours, minutes, seconds and
-milliseconds - seconds are the default if a unit is ommited.
+milliseconds - seconds are the default if a unit is omitted.
Can be given as a range which causes each thread to choose randomly out of the
range.
.TP
laid out or updated on disk, only that will be done. The actual job contents
are not executed.
.TP
+.BI allow_file_create \fR=\fPbool
+If true, fio is permitted to create files as part of its workload. This is
+the default behavior. If this option is false, then fio will error out if the
+files it needs to use don't already exist. Default: true.
+.TP
+.BI allow_mounted_write \fR=\fPbool
+If this isn't set, fio will abort jobs that are destructive (eg 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.
+.TP
.BI pre_read \fR=\fPbool
If this is given, files will be pre-read into memory before starting the given
IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
.BI experimental_verify \fR=\fPbool
Enable experimental verification.
.TP
+.BI verify_state_save \fR=\fPbool
+When a job exits during the write phase of a verify workload, save its
+current state. This allows fio to replay up until that point, if the
+verify state is loaded for the verify read phase.
+.TP
+.BI verify_state_load \fR=\fPbool
+If a verify termination trigger was used, fio stores the current write
+state of each thread. This can be used at verification time so that fio
+knows how far it should verify. Without this information, fio will run
+a full verification pass, according to the settings in the job file used.
+.TP
.B stonewall "\fR,\fP wait_for_previous"
Wait for preceding jobs in the job file to exit before starting this one.
\fBstonewall\fR implies \fBnew_group\fR.
from. Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
single specified device regardless of the device it was recorded from.
.TP
+.BI replay_align \fR=\fPint
+Force alignment of IO offsets and lengths in a trace to this power of 2 value.
+.TP
+.BI replay_scale \fR=\fPint
+Scale sector offsets down by this factor when replaying traces.
+.TP
+.BI per_job_logs \fR=\fPbool
+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.
+.TP
.BI write_bw_log \fR=\fPstr
If given, write a bandwidth log of the jobs in this job file. Can be used to
store data of the bandwidth of the jobs in their lifetime. The included
fio_generate_plots script uses gnuplot to turn these text files into nice
graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
option, the postfix is _bw.x.log, where x is the index of the job (1..N,
-where N is the number of jobs)
+where N is the number of jobs). If \fBper_job_logs\fR is false, then the
+filename will not include the job index.
.TP
.BI write_lat_log \fR=\fPstr
Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
filename is given with this option, the default filename of
"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.
+append the type of log. If \fBper_job_logs\fR is false, then the filename will
+not include the job index.
.TP
.BI write_iops_log \fR=\fPstr
Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
option, the default filename of "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.
+is given, fio will still append the type of log. If \fBper_job_logs\fR is false,
+then the filename will not include the job index.
.TP
.BI log_avg_msec \fR=\fPint
By default, fio will log an entry in the iops, latency, or bw log for every
\fB\-\-inflate-log\fR command line parameter. The files will be stored with a
\fB\.fz\fR suffix.
.TP
+.BI block_error_percentiles \fR=\fPbool
+If set, record errors in trim block-sized units from writes and trims and output
+a histogram of how many trims it took to get to errors, and what kind of error
+was encountered.
+.TP
.BI disable_lat \fR=\fPbool
Disable measurements of total latency numbers. Useful only for cutting
back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at
Enable the reporting of percentiles of completion latencies.
.TP
.BI percentile_list \fR=\fPfloat_list
-Overwrite the default list of percentiles for completion
-latencies. Each number is a floating number in the range (0,100], and
-the maximum length of the list is 20. Use ':' to separate the
+Overwrite the default list of percentiles for completion latencies and the
+block error histogram. Each number is a floating number in the range (0,100],
+and the maximum length of the list is 20. Use ':' to separate the
numbers. For example, \-\-percentile_list=99.5:99.9 will cause fio to
report the values of completion latency below which 99.5% and 99.9% of
the observed latencies fell, respectively.
used and must be omitted unless it is a valid UDP multicast address.
.TP
.BI (net,netsplice)port \fR=\fPint
-The TCP or UDP port to bind to or connect to.
+The TCP or UDP port to bind to or connect to. If this is used with
+\fBnumjobs\fR to spawn multiple instances of the same job type, then
+this will be the starting port number since fio will use a range of ports.
.TP
.BI (net,netsplice)interface \fR=\fPstr
The IP address of the network interface used to send or receive UDP multicast
send back. For UDP multicast traffic pingpong=1 should only be set for a single
reader when multiple readers are listening to the same address.
.TP
+.BI (net, window_size) \fR=\fPint
+Set the desired socket buffer size for the connection.
+.TP
+.BI (net, mss) \fR=\fPint
+Set the TCP maximum segment size (TCP_MAXSEG).
+.TP
.BI (e4defrag,donorname) \fR=\fPstr
File will be used as a block donor (swap extents between files)
.TP
.TP
.BI (rbd)clientname \fR=\fPstr
Specifies the username (without the 'client.' prefix) used to access the Ceph cluster.
+.TP
+.BI (mtd)skipbad \fR=\fPbool
+Skip operations against known bad blocks.
.SH OUTPUT
While running, \fBfio\fR will display the status of the created jobs. For
example:
fio \-\-client=server \-\-remote-config /path/to/file.fio
-Then the fio serer will open this local (to the server) job file instead
+Then fio will open this local (to the server) job file instead
of being passed one from the client.
+
+If you have many servers (example: 100 VMs/containers), you can input a pathname
+of a file containing host IPs/names as the parameter value for the \-\-client option.
+For example, here is an example "host.list" file containing 2 hostnames:
+
+host1.your.dns.domain
+.br
+host2.your.dns.domain
+
+The fio command would then be:
+
+fio \-\-client=host.list <job file>
+
+In this mode, you cannot input server-specific parameters or job files, and all
+servers receive the same job file.
+
+In order to enable fio \-\-client runs utilizing a shared filesystem from multiple hosts,
+fio \-\-client now prepends the IP address of the server to the filename. For example,
+if fio is using directory /mnt/nfs/fio and is writing filename fileio.tmp,
+with a \-\-client hostfile
+containing two hostnames h1 and h2 with IP addresses 192.168.10.120 and 192.168.10.121, then
+fio will create two files:
+
+/mnt/nfs/fio/192.168.10.120.fileio.tmp
+.br
+/mnt/nfs/fio/192.168.10.121.fileio.tmp
+
.SH AUTHORS
.B fio
was written by Jens Axboe <jens.axboe@oracle.com>,
-now Jens Axboe <jaxboe@fusionio.com>.
+now Jens Axboe <axboe@fb.com>.
.br
This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
on documentation by Jens Axboe.
projects / fio.git / blobdiff