Add randtrimwrite data direction

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index d40b42479adfe811ba3deee7ae601eb22c56d11f..4324a9750954624e040056d90502a31d93ebfa11 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -67,8 +67,8 @@ List all commands defined by \fIioengine\fR, or print help for \fIcommand\fR
 defined by \fIioengine\fR. If no \fIioengine\fR is given, list all
 available ioengines.
 .TP
-.BI \-\-showcmd \fR=\fPjobfile
-Convert \fIjobfile\fR to a set of command\-line options.
+.BI \-\-showcmd
+Convert given \fIjobfile\fRs to a set of command\-line options.
 .TP
 .BI \-\-readonly
 Turn on safety read\-only checks, preventing writes and trims. The \fB\-\-readonly\fR
@@ -900,7 +900,15 @@ Random mixed reads and writes.
 .TP
 .B trimwrite
 Sequential trim+write sequences. Blocks will be trimmed first,
-then the same blocks will be written to.
+then the same blocks will be written to. So if `io_size=64K' is specified,
+Fio will trim a total of 64K bytes and also write 64K bytes on the same
+trimmed blocks. This behaviour will be consistent with `number_ios' or
+other Fio options limiting the total bytes or number of I/O's.
+.TP
+.B randtrimwrite
+Like
+.B trimwrite ,
+but uses random offsets rather than sequential writes.
 .RE
 .P
 Fio defaults to read if the option is not specified. For the mixed I/O
@@ -2488,11 +2496,11 @@ Specify the label or UUID of the DAOS pool to connect to.
 Specify the label or UUID of the DAOS container to open.
 .TP
 .BI (dfs)chunk_size
-Specificy a different chunk size (in bytes) for the dfs file.
+Specify a different chunk size (in bytes) for the dfs file.
 Use DAOS container's chunk size by default.
 .TP
 .BI (dfs)object_class
-Specificy a different object class for the dfs file.
+Specify a different object class for the dfs file.
 Use DAOS container's object class by default.
 .TP
 .BI (nfs)nfs_url
@@ -3606,6 +3614,16 @@ EILSEQ) until the runtime is exceeded or the I/O size specified is
 completed. If this option is used, there are two more stats that are
 appended, the total error count and the first error. The error field given
 in the stats is the first error that was hit during the run.
+.RS
+.P
+Note: a write error from the device may go unnoticed by fio when using buffered
+IO, as the write() (or similar) system call merely dirties the kernel pages,
+unless `sync' or `direct' is used. Device IO errors occur when the dirty data is
+actually written out to disk. If fully sync writes aren't desirable, `fsync' or
+`fdatasync' can be used as well. This is specific to writes, as reads are always
+synchronous.
+.RS
+.P
 The allowed values are:
 .RS
 .RS