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
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
.TP
.BI write_iops_log \fR=\fPstr
Same as \fBwrite_bw_log\fR, but writes an IOPS file (e.g.
-`name_iops.x.log') instead. See \fBwrite_bw_log\fR for
-details about the filename format and the \fBLOG FILE FORMATS\fR section for how data
-is structured within the file.
+`name_iops.x.log`) instead. Because fio defaults to individual
+I/O logging, the value entry in the IOPS log will be 1 unless windowed
+logging (see \fBlog_avg_msec\fR) has been enabled. See
+\fBwrite_bw_log\fR for details about the filename format and \fBLOG
+FILE FORMATS\fR for how data is structured within the file.
.TP
.BI log_avg_msec \fR=\fPint
By default, fio will log an entry in the iops, latency, or bw log for every
I/O is a TRIM
.RE
.P
-The entry's `block size' is always in bytes. The `offset' is the offset, in bytes,
-from the start of the file, for that particular I/O. The logging of the offset can be
+The entry's `block size' is always in bytes. The `offset' is the position in bytes
+from the start of the file for that particular I/O. The logging of the offset can be
toggled with \fBlog_offset\fR.
.P
-Fio defaults to logging every individual I/O. When IOPS are logged for individual
-I/Os the `value' entry will always be 1. If windowed logging is enabled through
-\fBlog_avg_msec\fR, fio logs the average values over the specified period of time.
-If windowed logging is enabled and \fBlog_max_value\fR is set, then fio logs
-maximum values in that window instead of averages. Since `data direction', `block size'
-and `offset' are per\-I/O values, if windowed logging is enabled they
-aren't applicable and will be 0.
+Fio defaults to logging every individual I/O but when windowed logging is set
+through \fBlog_avg_msec\fR, either the average (by default) or the maximum
+(\fBlog_max_value\fR is set) `value' seen over the specified period of time
+is recorded. Each `data direction' seen within the window period will aggregate
+its values in a separate row. Further, when using windowed logging the `block
+size' and `offset' entries will always contain 0.
.SH CLIENT / SERVER
Normally fio is invoked as a stand\-alone application on the machine where the
I/O workload should be generated. However, the backend and frontend of fio can
projects / fio.git / blobdiff