Document that write_iolog is unsafe for concurrent jobs

[fio.git] / README

diff --git a/README b/README
index 0f91c66ff6430123032cf890f9bed826401ea4b3..de06fb10ad4031ebe5d727630c7171db6ad22dd6 100644 (file)
--- a/README
+++ b/README
@@ -274,7 +274,9 @@ The job file parameters are:
                        and length entries being in bytes.
        write_iolog=x   Write an iolog to file 'x' in the same format as iolog.
                        The iolog options are exclusive, if both given the
-                       read iolog will be performed.
+                       read iolog will be performed.  Specify a separate file
+                       for each job, otherwise the iologs will be interspersed
+                       and the file may be corrupt.
        write_bw_log    Write a bandwidth log.
        write_lat_log   Write a latency log.
        lockmem=x       Lock down x amount of memory on the machine, to