Mixed random reads and writes.
.RE
.P
-For mixed I/O, the default split is 50/50. For random I/O, the number of I/Os
-to perform before getting a new offset can be specified by appending
-`:\fIint\fR' to the pattern type. The default is 1.
+For mixed I/O, the default split is 50/50. For certain types of io the result
+may still be skewed a bit, since the speed may be different. It is possible to
+specify a number of IO's to do before getting a new offset, this is one by
+appending a `:\fI<nr>\fR to the end of the string given. For a random read, it
+would look like \fBrw=randread:8\fR for passing in an offset modifier with a
+value of 8. See the \fBrw_sequencer\fR option.
.RE
.TP
+.BI rw_sequencer \fR=\fPstr
+If an offset modifier is given by appending a number to the \fBrw=<str>\fR line,
+then this option controls how that number modifies the IO offset being
+generated. Accepted values are:
+.RS
+.RS
+.TP
+.B sequential
+Generate sequential offset
+.TP
+.B identical
+Generate the same offset
+.RE
+.P
+\fBsequential\fR is only useful for random IO, where fio would normally
+generate a new random offset for every IO. If you append eg 8 to randread, you
+would get a new random offset for every 8 IO's. The result would be a seek for
+only every 8 IO's, instead of for every IO. Use \fBrw=randread:8\fR to specify
+that. As sequential IO is already sequential, setting \fBsequential\fR for that
+would not result in any differences. \fBidentical\fR behaves in a similar
+fashion, except it sends the same offset 8 number of times before generating a
+new offset.
+.RE
+.P
+.TP
.BI kb_base \fR=\fPint
The base unit for a kilobyte. The defacto base is 2^10, 1024. Storage
manufacturers like to use 10^3 or 1000 as a base ten unit instead, for obvious
.BI size \fR=\fPint
Total size of I/O for this job. \fBfio\fR will run until this many bytes have
been transfered, unless limited by other options (\fBruntime\fR, for instance).
-Unless \fBnr_files\fR and \fBfilesize\fR options are given, this amount will be
+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 the files do not exist, size
must be given.
Linux native asynchronous I/O.
.TP
.B posixaio
-glibc POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3).
+POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3).
+.TP
+.B solarisaio
+Solaris native asynchronous I/O.
+.TP
+.B windowsaio
+Windows native asynchronous I/O.
.TP
.B mmap
File is memory mapped with \fImmap\fR\|(2) and data copied using
.RE
.TP
.BI iodepth \fR=\fPint
-Number of I/O units to keep in flight against the file. Default: 1.
+Number of I/O units to keep in flight against the file. Note that increasing
+iodepth beyond 1 will not affect synchronous ioengines (except for small
+degress when verify_async is in use). Even async engines my impose OS
+restrictions causing the desired depth not to be achieved. This may happen on
+Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is
+not async on that OS. Keep an eye on the IO depth distribution in the
+fio output to verify that the achieved depth is as expected. Default: 1.
.TP
.BI iodepth_batch \fR=\fPint
Number of I/Os to submit at once. Default: \fBiodepth\fR.
everything is read back and verified. You may want to verify continually
instead for a variety of reasons. Fio stores the meta data associated with an
IO block in memory, so for large verify workloads, quite a bit of memory would
-be used up holding this meta data. If this option is enabled, fio will verify
-the previously written blocks before continuing to write new ones.
+be used up holding this meta data. If this option is enabled, fio will write
+only N blocks before verifying these blocks.
.TP
.BI verify_backlog_batch \fR=\fPint
Control how many blocks fio will verify if verify_backlog is set. If not set,
will default to the value of \fBverify_backlog\fR (meaning the entire queue is
-read back and verified).
+read back and verified). If \fBverify_backlog_batch\fR is less than
+\fBverify_backlog\fR then not all blocks will be verified, if
+\fBverify_backlog_batch\fR is larger than \fBverify_backlog\fR, some blocks
+will be verified more than once.
.TP
.B stonewall
Wait for preceeding jobs in the job file to exit before starting this one.
Replay the I/O patterns contained in the specified file generated by
\fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
.TP
+.BI replay_no_stall \fR=\fPint
+While replaying I/O patterns using \fBread_iolog\fR the default behavior
+attempts to respect timing information between I/Os. Enabling
+\fBreplay_no_stall\fR causes I/Os to be replayed as fast as possible while
+still respecting ordering.
+.TP
+.BI replay_redirect \fR=\fPstr
+While replaying I/O patterns using \fBread_iolog\fR the default behavior
+is to replay the IOPS onto the major/minor device that each IOP was recorded
+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
.B 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
graphs. See \fBwrite_log_log\fR for behaviour of given filename. For this
option, the postfix is _bw.log.
.TP
-.B write_lat_log
+.B 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.log"
is used. Even if the filename is given, fio will still append the type of log.
.PD
.SH TERSE OUTPUT
If the \fB\-\-minimal\fR option is given, the results will be printed in a
-semicolon-delimited format suitable for scripted use. Note that the first
+semicolon-delimited format suitable for scripted use - a job description
+(if provided) follows on a new line. Note that the first
number in the line is the version number. If the output has to be changed
for some reason, this number will be incremented by 1 to signify that
change. The fields are:
.B <=1, 2, 4, 8, 16, 32, >=64
.RE
.P
-IO latency distribution (ms):
+IO latency distribution:
+.RS
+Microseconds:
+.RS
+.B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000
+.RE
+Milliseconds:
+.RS
+.B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
+.RE
+.RE
+.P
+Error Info (dependant on continue_on_error, default off):
.RS
-.B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
+.B total # errors, first error code
.RE
.P
-.B text description
+.B text description (if provided in config - appears on newline)
.RE
.SH AUTHORS
.B fio
projects / fio.git / blobdiff