Add option for controlling buffer scrambling

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index b67a201efd78635953b46ded0538de6110ec3e46..cc2df9b72421486d96d47e2d72220a0a5848c55a 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -481,6 +481,13 @@ refill_buffers     If this option is given, fio will refill the IO buffers
                isn't specified, naturally. If data verification is enabled,
                refill_buffers is also automatically enabled.
 
+scramble_buffers=bool  If refill_buffers is too costly and the target is
+               using data deduplication, then setting this option will
+               slightly modify the IO buffer contents to defeat normal
+               de-dupe attempts. This is not enough to defeat more clever
+               block compression attempts, but it will stop naive dedupe of
+               blocks. Default: true.
+
 nrfiles=int    Number of files to use for this job. Defaults to 1.
 
 openfiles=int  Number of files to keep open at the same time. Defaults to