Add option for refilling IO buffers on each submit

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index bbf5715ae229f0830d2195308ca2249256fed706..36e42aaf6b9defb210d83d0b538284bea7f6a4d6 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -336,6 +336,11 @@ bs_unaligned       If this option is given, any byte size value within bsrange
 zero_buffers   If this option is given, fio will init the IO buffers to
                all zeroes. The default is to fill them with random data.
 
+refill_buffers If this option is given, fio will refill the IO buffers
+               on every submit. The default is to only fill it at init
+               time and reuse that data. Only makes sense if zero_buffers
+               isn't specified, naturally.
+
 nrfiles=int    Number of files to use for this job. Defaults to 1.
 
 openfiles=int  Number of files to keep open at the same time. Defaults to
@@ -454,7 +459,11 @@ fsync=int  If writing to a file, issue a sync of the dirty data
                not sync the file. The exception is the sg io engine, which
                synchronizes the disk cache anyway.
 
-overwrite=bool If writing to a file, setup the file first and do overwrites.
+overwrite=bool If true, writes to a file will always overwrite existing
+               data. If the file doesn't already exist, it will be
+               created before the write phase begins. If the file exists
+               and is large enough for the specified write phase, nothing
+               will be done.
 
 end_fsync=bool If true, fsync file contents when the job exits.