Add 'stats' option

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 15ed42549580a659c82cd5febb7e4be6a441addc..5d378f3d9a75cf7c0e1cd7ca95f65ecaee060d58 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -886,7 +886,8 @@ Target file/device
        If this isn't set, fio will abort jobs that are destructive (e.g. that write)
        to what appears to be a mounted device or partition. This should help catch
        creating inadvertently destructive tests, not realizing that the test will
-       destroy data on the mounted file system. Default: false.
+       destroy data on the mounted file system. Note that some platforms don't allow
+       writing against a mounted device regardless of this option. Default: false.
 
 .. option:: pre_read=bool
 
@@ -1104,7 +1105,7 @@ I/O type
 .. option:: fdatasync=int
 
        Like :option:`fsync` but uses :manpage:`fdatasync(2)` to only sync data and
-       not metadata blocks.  In FreeBSD and Windows there is no
+       not metadata blocks.  In Windows, FreeBSD, and DragonFlyBSD there is no
        :manpage:`fdatasync(2)`, this falls back to using :manpage:`fsync(2)`.
 
 .. option:: write_barrier=int
@@ -1426,7 +1427,9 @@ Buffers and memory
 .. option:: invalidate=bool
 
        Invalidate the buffer/page cache parts for this file prior to starting
-       I/O. Defaults to true.
+       I/O if the platform and file type support it. Defaults to true.
+       This will be ignored if :option:`pre_read` is also specified for the
+       same job.
 
 .. option:: sync=bool
 
@@ -1513,7 +1516,7 @@ I/O size
        Fio will divide this size between the available files determined by options
        such as :option:`nrfiles`, :option:`filename`, unless :option:`filesize` is
        specified by the job. If the result of division happens to be 0, the size is
-       set to the physical size of the given files or devices.
+       set to the physical size of the given files or devices if they exist.
        If this option is not specified, fio will use the full size of the given
        files or devices.  If the files do not exist, size must be given. It is also
        possible to give size as a percentage between 1 and 100. If ``size=20%`` is
@@ -2590,6 +2593,12 @@ Measurements and reporting
        all jobs in a file will be part of the same reporting group, unless
        separated by a :option:`stonewall`.
 
+.. option:: stats
+
+       By default, fio collects and shows final output results for all jobs
+       that run. If this option is set to 0, then fio will ignore it in
+       the final stat output.
+
 .. option:: write_bw_log=str
 
        If given, write a bandwidth log for this job. Can be used to store data of