Convert \fIjobfile\fR to a set of command\-line options.
.TP
.BI \-\-readonly
-Turn on safety read\-only checks, preventing writes. The \fB\-\-readonly\fR
+Turn on safety read\-only checks, preventing writes and trims. The \fB\-\-readonly\fR
option is an extra safety guard to prevent users from accidentally starting
-a write workload when that is not desired. Fio will only write if
-`rw=write/randwrite/rw/randrw' is given. This extra safety net can be used
-as an extra precaution as \fB\-\-readonly\fR will also enable a write check in
-the I/O engine core to prevent writes due to unknown user space bug(s).
+a write or trim workload when that is not desired. Fio will only modify the
+device under test if `rw=write/randwrite/rw/randrw/trim/randtrim/trimwrite'
+is given. This safety net can be used as an extra precaution.
.TP
.BI \-\-eta \fR=\fPwhen
Specifies when real\-time ETA estimate should be printed. \fIwhen\fR may
Sequential writes.
.TP
.B trim
-Sequential trims (Linux block devices only).
+Sequential trims (Linux block devices and SCSI character devices only).
.TP
.B randread
Random reads.
Random writes.
.TP
.B randtrim
-Random trims (Linux block devices only).
+Random trims (Linux block devices and SCSI character devices only).
.TP
.B rw,readwrite
Sequential mixed reads and writes.
and that some blocks may be read/written more than once. If this option is
used with \fBverify\fR and multiple blocksizes (via \fBbsrange\fR),
only intact blocks are verified, i.e., partially\-overwritten blocks are
-ignored.
+ignored. With an async I/O engine and an I/O depth > 1, it is possible for
+the same block to be overwritten, which can cause verification errors. Either
+do not use norandommap in this case, or also use the lfsr random generator.
.TP
.BI softrandommap \fR=\fPbool
See \fBnorandommap\fR. If fio runs with the random block map enabled and
90% 4k writes and 10% 8k writes, you would specify:
.RS
.P
-bssplit=2k/50:4k/50,4k/90,8k/10
+bssplit=2k/50:4k/50,4k/90:8k/10
.RE
.P
Fio supports defining up to 64 different weights for each data direction.
ioctl, or if the target is an sg character device we use
\fBread\fR\|(2) and \fBwrite\fR\|(2) for asynchronous
I/O. Requires \fBfilename\fR option to specify either block or
-character devices. The sg engine includes engine specific options.
+character devices. This engine supports trim operations. The
+sg engine includes engine specific options.
.TP
.B null
Doesn't transfer any data, just pretends to. This is mainly used to
.BI (sg)writefua \fR=\fPbool
With writefua option set to 1, write operations include the force
unit access (fua) flag. Default: 0.
+.TP
+.BI (sg)sg_write_mode \fR=\fPstr
+Specify the type of write commands to issue. This option can take three
+values:
+.RS
+.RS
+.TP
+.B write (default)
+Write opcodes are issued as usual
+.TP
+.B verify
+Issue WRITE AND VERIFY commands. The BYTCHK bit is set to 0. This
+directs the device to carry out a medium verification with no data
+comparison. The writefua option is ignored with this selection.
+.TP
+.B same
+Issue WRITE SAME commands. This transfers a single block to the device
+and writes this same block of data to a contiguous sequence of LBAs
+beginning at the specified offset. fio's block size parameter
+specifies the amount of data written with each command. However, the
+amount of data actually transferred to the device is equal to the
+device's block (sector) size. For a device with 512 byte sectors,
+blocksize=8k will write 16 sectors with each command. fio will still
+generate 8k of data for each command butonly the first 512 bytes will
+be used and transferred to the device. The writefua option is ignored
+with this selection.
+
.SS "I/O depth"
.TP
.BI iodepth \fR=\fPint
replay, the file needs to be turned into a blkparse binary data file first
(`blkparse <device> \-o /dev/null \-d file_for_fio.bin').
.TP
+.BI read_iolog_chunked \fR=\fPbool
+Determines how iolog is read. If false (default) entire \fBread_iolog\fR will
+be read at once. If selected true, input from iolog will be read gradually.
+Useful when iolog is very large, or it is generated.
+.TP
.BI replay_no_stall \fR=\fPbool
When replaying I/O with \fBread_iolog\fR the default behavior is to
attempt to respect the timestamps within the log and replay them with the
Scale sector offsets down by this factor when replaying traces.
.SS "Threads, processes and job synchronization"
.TP
+.BI replay_skip \fR=\fPstr
+Sometimes it's useful to skip certain IO types in a replay trace. This could
+be, for instance, eliminating the writes in the trace. Or not replaying the
+trims/discards, if you are redirecting to a device that doesn't support them.
+This option takes a comma separated list of read, write, trim, sync.
+.TP
.BI thread
Fio defaults to creating jobs by using fork, however if this option is
given, fio will create jobs by using POSIX Threads' function
given is a read or random read, fio will assume that it should verify a
previously written file. If the data direction includes any form of write,
the verify will be of the newly written data.
+.P
+To avoid false verification errors, do not use the norandommap option when
+verifying data with async I/O engines and I/O depths > 1. Or use the
+norandommap and the lfsr random generator together to avoid writing to the
+same offset with muliple outstanding I/Os.
.RE
.TP
.BI verify_offset \fR=\fPint
projects / fio.git / blobdiff