HOWTO: update to include iolog replay

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index c1b768d2841d131073e271930c085f5a6a321e60..3f8acee15221f321a8838fa907759d3d96455e2e 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1066,6 +1066,10 @@ random_generator=str     Fio supports the following engines for generating
 
 nice=int       Run the job with the given nice value. See man nice(2).
 
+     On Windows, values less than -15 set the process class to "High";
+     -1 through -15 set "Above Normal"; 1 through 15 "Below Normal";
+     and above 15 "Idle" priority class.
+
 prio=int       Set the io priority value of this job. Linux limits us to
                a positive value between 0 and 7, with 0 being the highest.
                See man ionice(1). Refer to an appropriate manpage for
@@ -1554,10 +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 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
-               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
@@ -1569,13 +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
-               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.
@@ -1681,6 +1686,10 @@ log_store_compressed=bool        If set, fio will store the log files in a
                the --inflate-log command line parameter. The files will be
                stored with a .fz suffix.
 
+log_unix_epoch=bool    If set, fio will log Unix timestamps to the log
+               files produced by enabling write_type_log for each log type, instead
+               of the default zero-based timestamps.
+
 block_error_percentiles=bool   If set, record errors in trim block-sized
                units from writes and trims and output a histogram of
                how many trims it took to get to errors, and what kind