Basic support for dedupe

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 73e58ff695c3384df30094d6c15ebe9ed615460f..23746cec199e05c6a34ed007794f5c45abc6e8e5 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -565,12 +565,20 @@ buffer_compress_chunk=int See buffer_compress_percentage. This
                alternate random and zeroed data throughout the IO
                buffer.
 
-buffer_pattern=str     If set, fio will fill the io buffers with this pattern.
-               If not set, the contents of io buffers is defined by the other
-               options related to buffer contents. The setting can be any
-               pattern of bytes, and can be prefixed with 0x for hex values.
-               It may also be a string, where the string must then be
-               wrapped with "".
+buffer_pattern=str     If set, fio will fill the io buffers with this
+               pattern. If not set, the contents of io buffers is defined by
+               the other options related to buffer contents. The setting can
+               be any pattern of bytes, and can be prefixed with 0x for hex
+               values. It may also be a string, where the string must then
+               be wrapped with "".
+
+dedupe_percentage=int  If set, fio will generate this percentage of
+               identical buffers when writing. These buffers will be
+               naturally dedupable. The contents of the buffers depend on
+               what other buffer compression settings have been set. It's
+               possible to have the individual buffers either fully
+               compressible, or not at all. This option only controls the
+               distribution of unique buffers.
 
 nrfiles=int    Number of files to use for this job. Defaults to 1.