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
 
 
 $ 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 "${VARNAME}" as part of an option value (in other
 words, on the right of the `='), will be expanded to the value of the
 fio also supports environment variable expansion in job files. Any
 substring of the form "${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.
 
 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
 -------------------------------
 
 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.
 
 
                        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.
                        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
 
                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
 
 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