Documentation: add note about how many bssplit and zones fio supports

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index cd0fcf34861bda196954a031e758a385d521c810..4caaf542e0e4b89f4156309469e476700f4b372f 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1293,6 +1293,9 @@ I/O type
 
                random_distribution=zoned_abs=60/20G:30/100G:10/500g
 
+       For both **zoned** and **zoned_abs**, fio supports defining up to
+       256 separate zones.
+
        Similarly to how :option:`bssplit` works for setting ranges and
        percentages of block sizes. Like :option:`bssplit`, it's possible to
        specify separate zones for reads, writes, and trims. If just one set
@@ -1388,34 +1391,39 @@ Block size
 
 .. option:: bssplit=str[,str][,str]
 
-       Sometimes you want even finer grained control of the block sizes issued, not
-       just an even split between them.  This option allows you to weight various
-       block sizes, so that you are able to define a specific amount of block sizes
-       issued. The format for this option is::
+       Sometimes you want even finer grained control of the block sizes
+       issued, not just an even split between them.  This option allows you to
+       weight various block sizes, so that you are able to define a specific
+       amount of block sizes issued. The format for this option is::
 
                bssplit=blocksize/percentage:blocksize/percentage
 
-       for as many block sizes as needed. So if you want to define a workload that
-       has 50% 64k blocks, 10% 4k blocks, and 40% 32k blocks, you would write::
+       for as many block sizes as needed. So if you want to define a workload
+       that has 50% 64k blocks, 10% 4k blocks, and 40% 32k blocks, you would
+       write::
 
                bssplit=4k/10:64k/50:32k/40
 
-       Ordering does not matter. If the percentage is left blank, fio will fill in
-       the remaining values evenly. So a bssplit option like this one::
+       Ordering does not matter. If the percentage is left blank, fio will
+       fill in the remaining values evenly. So a bssplit option like this one::
 
                bssplit=4k/50:1k/:32k/
 
-       would have 50% 4k ios, and 25% 1k and 32k ios. The percentages always add up
-       to 100, if bssplit is given a range that adds up to more, it will error out.
+       would have 50% 4k ios, and 25% 1k and 32k ios. The percentages always
+       add up to 100, if bssplit is given a range that adds up to more, it
+       will error out.
 
        Comma-separated values may be specified for reads, writes, and trims as
        described in :option:`blocksize`.
 
-       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::
+       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
 
+       Fio supports defining up to 64 different weights for each data
+       direction.
+
 .. option:: blocksize_unaligned, bs_unaligned
 
        If set, fio will issue I/O units with any size within