Get rid of warning on platforms for casting char -> int

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index e54382b19b5e35beaa907b1cb263081d5c8bab44..ee899b8fdb6c402814086dde41f986d152c456c9 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -348,11 +348,25 @@ kb_base=int       The base unit for a kilobyte. The defacto base is 2^10, 1024.
 randrepeat=bool        For random IO workloads, seed the generator in a predictable
                way so that results are repeatable across repetitions.
 
 randrepeat=bool        For random IO workloads, seed the generator in a predictable
                way so that results are repeatable across repetitions.
 

-fallocate=bool 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.  If using ZFS on Solaris this must be
-               set to 0 because ZFS doesn't support it.
+use_os_rand=bool 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.
+
+fallocate=str  Whether pre-allocation is performed when laying down files.
+               Accepted values are:
+
+                       none            Do not pre-allocate space
+                       posix           Pre-allocate via posix_fallocate()
+                       keep            Pre-allocate via fallocate() with
+                                       FALLOC_FL_KEEP_SIZE set
+                       0               Backward-compatible alias for 'none'
+                       1               Backward-compatible alias for 'posix'
+
+               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'.

 
 fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
                on what IO patterns it is likely to issue. Sometimes you
 
 fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
                on what IO patterns it is likely to issue. Sometimes you


@@ -375,10 +389,15 @@ filesize=int      Individual file sizes. May be a range, in which case fio
                and limited to 'size' in total (if that is given). If not
                given, each created file is the same size.
 
                and limited to 'size' in total (if that is given). If not
                given, each created file is the same size.
 

-fill_device=bool Sets size to something really large and waits for ENOSPC (no
+fill_device=bool
+fill_fs=bool   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
                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.
+               point will be filled first then IO started on 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.

 
 blocksize=int
 bs=int         The block size used for the io units. Defaults to 4k. Values
 
 blocksize=int
 bs=int         The block size used for the io units. Defaults to 4k. Values


@@ -926,6 +945,11 @@ verify_fatal=bool  Normally fio will keep checking the entire contents
                option is set, fio will exit the job on the first observed
                failure.
 
                option is set, fio will exit the job on the first observed
                failure.
 

+verify_dump=bool       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.
+

 verify_async=int       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 verification instead,
 verify_async=int       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 verification instead,


@@ -993,7 +1017,8 @@ zoneskip=int       Skip the specified number of bytes when zonesize data has
                io on zones of a file.
 
 write_iolog=str        Write the issued io patterns to the specified file. See
                io on zones of a file.
 
 write_iolog=str        Write the issued io patterns to the specified file. See

-               read_iolog.
+               read_iolog.  Specify a separate file for each job, otherwise
+               the iologs will be interspersed and the file may be corrupt.

 
 read_iolog=str Open an iolog with the specified file name and replay the
                io patterns it contains. This can be used to store a
 
 read_iolog=str Open an iolog with the specified file name and replay the
                io patterns it contains. This can be used to store a