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
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
\fBblktrace\fR\|(8) for how to capture such logging data. For blktrace
replay, the file needs to be turned into a blkparse binary data file first
(`blkparse <device> \-o /dev/null \-d file_for_fio.bin').
+You can specify a number of files by separating the names with a ':' character.
+See the \fBfilename\fR option for information on how to escape ':' and '\'
+characters within the file names. These files will be sequentially assigned to
+job clones created by \fBnumjobs\fR.
+.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
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