Full readonly check

[fio.git] / README

diff --git a/README b/README
index 76aa22d69212e86b799ee15d2e4db3c5e5d4c987..b7fc96b6888d1032bf04cbbb5f8c5f309fa18e7c 100644 (file)
--- a/README
+++ b/README
@@ -71,12 +71,19 @@ $ fio
        --help          Print this page
        --cmdhelp=cmd   Print command help, "all" for all of them
        --showcmd       Turn a job file into command line options
+       --readonly      Turn on safety read-only checks
 
 Any parameters following the options will be assumed to be job files,
 unless they match a job file parameter. You can add as many as you want,
 each job file will be regarded as a separate group and fio will stonewall
 its execution.
 
+The --readonly switch is an extra safety guard to prevent accidentically
+turning on a write setting when that is not desired. Fio will only write
+if rw=write/randwrite/rw/randrw is given, but this extra safety net can
+be used as an extra precaution. It will also enable a write check in the
+io engine core to prevent an accidental write due to a fio bug.
+
 
 Job file
 --------