Add ability to invoke fallocate() FALLOC_FL_KEEP_SIZE.

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 8d5baa831d1c90f63ef60810a560b4238810cae4..ad5040b37372e93415b7783db9924934211213cf 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -214,10 +214,38 @@ reasons. Allow values are 1024 or 1000, with 1024 being the default.
 Seed the random number generator in a predictable way so results are repeatable
 across runs.  Default: true.
 .TP
-.BI fallocate \fR=\fPbool
-By default, fio will use fallocate() to advise the system of the size of the
-file we are going to write. This can be turned off with fallocate=0. May not
-be available on all supported platforms.
+.BI use_os_rand \fR=\fPbool
+Fio can either use the random generator supplied by the OS to generator random
+offsets, or it can use it's own internal generator (based on Tausworthe).
+Default is to use the internal generator, which is often of better quality and
+faster. Default: false.
+.TP
+.BI fallocate \fR=\fPstr
+Whether pre-allocation is performed when laying down files. Accepted values
+are:
+.RS
+.RS
+.TP
+.B none
+Do not pre-allocate space.
+.TP
+.B posix
+Pre-allocate via posix_fallocate().
+.TP
+.B keep
+Pre-allocate via fallocate() with FALLOC_FL_KEEP_SIZE set.
+.TP
+.B 0
+Backward-compatible alias for 'none'.
+.TP
+.B 1
+Backward-compatible alias for 'posix'.
+.RE
+.P
+May not be available on all supported platforms. 'keep' is only
+available on Linux. If using ZFS on Solaris this must be set to 'none'
+because ZFS doesn't support it. Default: 'posix'.
+.RE
 .TP
 .BI fadvise_hint \fR=\fPbool
 Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
@@ -231,11 +259,13 @@ 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.
 .TP
-.BI fill_device \fR=\fPbool
+.BI fill_device \fR=\fPbool "\fR,\fB fill_fs" \fR=\fPbool
 Sets size to something really large and waits for ENOSPC (no space left on
 device) as the terminating condition. Only makes sense with sequential write.
 For a read workload, the mount point will be filled first then IO started on
-the result.
+the result. This option doesn't make sense if operating on a raw device node,
+since the size of that is already known by the file system. Additionally,
+writing beyond end-of-device will not return ENOSPC there.
 .TP
 .BI filesize \fR=\fPirange
 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
@@ -692,6 +722,11 @@ has to be a hex number that starts with either "0x" or "0X". Use with
 If true, exit the job on the first observed verification failure.  Default:
 false.
 .TP
+.BI verify_dump \fR=\fPbool
+If set, dump the contents of both the original data block and the data block we
+read off disk to files. This allows later analysis to inspect just what kind of
+data corruption occurred. On by default.
+.TP
 .BI verify_async \fR=\fPint
 Fio will normally verify IO inline from the submitting thread. This option
 takes an integer describing how many async offload threads to create for IO
@@ -749,7 +784,9 @@ Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
 read.
 .TP
 .BI write_iolog \fR=\fPstr
-Write the issued I/O patterns to the specified file.
+Write the issued I/O patterns to the specified file.  Specify a separate file
+for each job, otherwise the iologs will be interspersed and the file may be
+corrupt.
 .TP
 .BI read_iolog \fR=\fPstr
 Replay the I/O patterns contained in the specified file generated by