HOWTO: make it clear that deviation is standard deviation

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 74475129fd417f85c083872b27d8d0486f88936a..b823eaed24a5b84b30bbf2d19ab5f4ef9f089ae0 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -961,6 +961,8 @@ random_generator=str        Fio supports the following engines for generating
 
                tausworthe      Strong 2^88 cycle random number generator
                lfsr            Linear feedback shift register generator
+               tausworthe64    Strong 64-bit 2^258 cycle random number
+                               generator
 
                Tausworthe is a strong random number generator, but it
                requires tracking on the side if we want to ensure that
@@ -1204,6 +1206,12 @@ allow_file_create=bool   If true, fio is permitted to create files as part
                option is false, then fio will error out if the files it
                needs to use don't already exist. Default: true.
 
+allow_mounted_write=bool       If this isn't set, fio will abort jobs that
+               are destructive (eg that write) to what appears to be a
+               mounted device or partition. This should help catch creating
+               inadvertently destructive tests, not realizing that the test
+               will destroy data on the mounted file system. Default: false.
+
 pre_read=bool  If this is given, files will be pre-read into memory before
                starting the given IO operation. This will also clear
                the 'invalidate' flag, since it is pointless to pre-read
@@ -1273,6 +1281,12 @@ verify=str       If writing to a file, fio can verify the file contents
                                verified for workloads that write data.
                                See also verify_pattern.
 
+                       pattern Verify a strict pattern. Normally fio includes
+                               a header with some basic information and
+                               checksumming, but if this option is set, only
+                               the specific pattern set with 'verify_pattern'
+                               is verified.
+
                        null    Only pretend to verify. Useful for testing
                                internals with ioengine=null, not for much
                                else.
@@ -1942,18 +1956,18 @@ Split up, the format is as follows:
        terse version, fio version, jobname, groupid, error
        READ status:
                Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
-               Submission latency: min, max, mean, deviation (usec)
-               Completion latency: min, max, mean, deviation (usec)
+               Submission latency: min, max, mean, stdev (usec)
+               Completion latency: min, max, mean, stdev (usec)
                Completion latency percentiles: 20 fields (see below)
-               Total latency: min, max, mean, deviation (usec)
-               Bw (KB/s): min, max, aggregate percentage of total, mean, deviation
+               Total latency: min, max, mean, stdev (usec)
+               Bw (KB/s): min, max, aggregate percentage of total, mean, stdev
        WRITE status:
                Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
-               Submission latency: min, max, mean, deviation (usec)
-               Completion latency: min, max, mean, deviation (usec)
+               Submission latency: min, max, mean, stdev (usec)
+               Completion latency: min, max, mean, stdev(usec)
                Completion latency percentiles: 20 fields (see below)
-               Total latency: min, max, mean, deviation (usec)
-               Bw (KB/s): min, max, aggregate percentage of total, mean, deviation
+               Total latency: min, max, mean, stdev (usec)
+               Bw (KB/s): min, max, aggregate percentage of total, mean, stdev
        CPU usage: user, system, context switches, major faults, minor faults
        IO depths: <=1, 2, 4, 8, 16, 32, >=64
        IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000