Fio 1.34.2

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index aec00e84e548f1c9d65952e73803d8fcb5df53e9..aa10dbc2bccadd9dbdab852d7cc1695b8404a498 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -158,6 +158,9 @@ specify:
 
 $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
 
+4.1 Environment variables
+-------------------------
+
 fio also supports environment variable expansion in job files. Any
 substring of the form "${VARNAME}" as part of an option value (in other
 words, on the right of the `='), will be expanded to the value of the
@@ -188,6 +191,20 @@ numjobs=4
 fio ships with a few example job files, you can also look there for
 inspiration.
 
+4.2 Reserved keywords
+---------------------
+
+Additionally, fio has a set of reserved keywords that will be replaced
+internally with the appropriate value. Those keywords are:
+
+$pagesize      The architecture page size of the running system
+$mb_memory     Megabytes of total memory in the system
+$ncpus         Number of online available CPUs
+
+These can be used on the command line or in the job file, and will be
+automatically substituted with the current system values when the job
+is run.
+
 
 5.0 Detailed list of parameters
 -------------------------------
@@ -794,6 +811,8 @@ verify=str  If writing to a file, fio can verify the file contents
 
                        sha256  Use sha256 as the checksum function.
 
+                       sha1    Use optimized sha1 as the checksum function.
+
                        meta    Write extra information about each io
                                (timestamp, block number etc.). The block
                                number is verified.
@@ -804,7 +823,11 @@ verify=str If writing to a file, fio can verify the file contents
 
                This option can be used for repeated burn-in tests of a
                system to make sure that the written data is also
-               correctly read back.
+               correctly read back. If the data direction given is
+               a read or random read, fio will assume that it should
+               verify a previously written file. If the data direction
+               includes any form of write, the verify will be of the
+               newly written data.
 
 verifysort=bool        If set, fio will sort written verify blocks when it deems
                it faster to read them back in a sorted manner. This is