Add support for different weights for reads and writes with bssplit

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 999f7778f37d9d9628f76189609411f7053e77b2..15f576d28fa2ff16038c6249d41da6d2f4d64357 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -367,6 +367,15 @@ bssplit=str        Sometimes you want even finer grained control of the
                always add up to 100, if bssplit is given a range that adds
                up to more, it will error out.
 
+               bssplit also supports giving separate splits to reads and
+               writes. The format is identical to what bs= accepts. You
+               have to separate the read and write parts with a comma. So
+               if you want a workload that has 50% 2k reads and 50% 4k reads,
+               while having 90% 4k writes and 10% 8k writes, you would
+               specify:
+
+               bssplit=2k/50:4k/50,4k/90,8k/10
+
 blocksize_unaligned
 bs_unaligned   If this option is given, any byte size value within bsrange
                may be used as a block range. This typically wont work with