HOWTO: update to include iolog replay

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/HOWTO b/HOWTO
index cf1024cff4dbb2a7f8ee888cae6d21d511b5096d..3f8acee15221f321a8838fa907759d3d96455e2e 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1558,10 +1558,10 @@ read_iolog=str  Open an iolog with the specified file name and replay the
 
 replay_no_stall=int When replaying I/O with read_iolog the default behavior
                is to attempt to respect the time stamps within the log and
 
 replay_no_stall=int When replaying I/O with read_iolog the default behavior
                is to attempt to respect the time stamps within the log and

-               replay them with the appropriate delay between IOPS.  By
+               replay them with the appropriate delay between IOPS. By

                setting this variable fio will not respect the timestamps and
                attempt to replay them as fast as possible while still
                setting this variable fio will not respect the timestamps and
                attempt to replay them as fast as possible while still

-               respecting ordering.  The result is the same I/O pattern to a
+               respecting ordering. The result is the same I/O pattern to a

                given device, but different timings.
 
 replay_redirect=str While replaying I/O patterns using read_iolog the
                given device, but different timings.
 
 replay_redirect=str While replaying I/O patterns using read_iolog the


@@ -1573,13 +1573,14 @@ replay_redirect=str While replaying I/O patterns using read_iolog the
                mapping.  Replay_redirect causes all IOPS to be replayed onto
                the single specified device regardless of the device it was
                recorded from. i.e. replay_redirect=/dev/sdc would cause all
                mapping.  Replay_redirect causes all IOPS to be replayed onto
                the single specified device regardless of the device it was
                recorded from. i.e. replay_redirect=/dev/sdc would cause all

-               IO in the blktrace to be replayed onto /dev/sdc.  This means
-               multiple devices will be replayed onto a single, if the trace
-               contains multiple devices.  If you want multiple devices to be
-               replayed concurrently to multiple redirected devices you must
-               blkparse your trace into separate traces and replay them with
-               independent fio invocations.  Unfortuantely this also breaks
-               the strict time ordering between multiple device accesses.
+               IO in the blktrace or iolog to be replayed onto /dev/sdc.
+               This means multiple devices will be replayed onto a single
+               device, if the trace contains multiple devices. If you want
+               multiple devices to be replayed concurrently to multiple
+               redirected devices you must blkparse your trace into separate
+               traces and replay them with independent fio invocations.
+               Unfortuantely this also breaks the strict time ordering
+               between multiple device accesses.

 
 replay_align=int       Force alignment of IO offsets and lengths in a trace
                to this power of 2 value.
 
 replay_align=int       Force alignment of IO offsets and lengths in a trace
                to this power of 2 value.