Document that write_iolog is unsafe for concurrent jobs
The write_iolog parameter should not be used in the global section since
each job will independently write to the same file. The output will be
interspersed and the file will be corrupt.
Document that each job should write to its own iolog file. This will
save users time when trying out the iolog feature for the first time.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Updated by me to make the same change to the man page.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/HOWTO b/HOWTO
index dc21afc..7c94329 100644
--- a/HOWTO
+++ b/HOWTO
@@ -988,7 +988,8 @@
io on zones of a file.
write_iolog=str Write the issued io patterns to the specified file. See
- read_iolog.
+ read_iolog. Specify a separate file for each job, otherwise
+ the iologs will be interspersed and the file may be corrupt.
read_iolog=str Open an iolog with the specified file name and replay the
io patterns it contains. This can be used to store a