Merge branch 'evelu-exec' of https://github.com/ErwanAliasr1/fio

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index f0914ba8216c42c9413a519bcddcc77bea679e83..59c7f1ffb82066544fad7239790d6f4b3da736f3 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1705,6 +1705,36 @@ Buffers and memory
        this option will also enable :option:`refill_buffers` to prevent every buffer
        being identical.
 
+.. option:: dedupe_mode=str
+
+       If ``dedupe_percentage=<int>`` is given, then this option controls how fio
+       generates the dedupe buffers.
+
+               **repeat**
+                       Generate dedupe buffers by repeating previous writes
+               **working_set**
+                       Generate dedupe buffers from working set
+
+       ``repeat`` is the default option for fio. Dedupe buffers are generated
+       by repeating previous unique write.
+
+       ``working_set`` is a more realistic workload.
+       With ``working_set``, ``dedupe_working_set_percentage=<int>`` should be provided.
+       Given that, fio will use the initial unique write buffers as its working set.
+       Upon deciding to dedupe, fio will randomly choose a buffer from the working set.
+       Note that by using ``working_set`` the dedupe percentage will converge
+       to the desired over time while ``repeat`` maintains the desired percentage
+       throughout the job.
+
+.. option:: dedupe_working_set_percentage=int
+
+       If ``dedupe_mode=<str>`` is set to ``working_set``, then this controls
+       the percentage of size of the file or device used as the buffers
+       fio will choose to generate the dedupe buffers from
+
+       Note that size needs to be explicitly provided and only 1 file per
+       job is supported
+
 .. option:: invalidate=bool
 
        Invalidate the buffer/page cache parts of the files to be used prior to