Theodore Tso wrote: > This is what I have added to the ext4 patch queue. > > - Ted > > Update Documentation/filesystems/ext4.txt > > Fix paragraph with recommendations on how to tune ext4 for benchmarks. > > Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> > diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt > index 845e691..19bb93f 100644 > --- a/Documentation/filesystems/ext4.txt > +++ b/Documentation/filesystems/ext4.txt > @@ -58,13 +58,18 @@ Note: More extensive information for getting started with ext4 can be > > # mount -t ext4 /dev/hda1 /wherever > > - - When comparing performance with other filesystems, remember that > - ext3/4 by default offers higher data integrity guarantees than most. > - So when comparing with a metadata-only journalling filesystem, such > - as ext3, use `mount -o data=writeback'. And you might as well use > - `mount -o nobh' too along with it. Making the journal larger than > - the mke2fs default often helps performance with metadata-intensive > - workloads. > + - When comparing performance with other filesystems, it's always > + important to try multiple workloads; very often a subtle change in a > + workload parameter can completely change the ranking of which > + filesystems do well compared to others. When comparing versus ext3, > + note that ext4 enables write barriers by default, while ext3 does > + not enable write barriers by default. So it is useful to use > + explicitly specify whether barriers are enabled or not when via the > + '-o barriers=[0|1]' mount option. That sentence doesn't quite parse... > + When tuning ext3 for best > + benchmark numbers, it is often worthwhile to try changing the data > + journaling mode; '-o data=writeback,nobh' can be faster for some > + workloads. It should probably be made obvious that this has a security implication (stale data exposed, right?) -Eric > + A large journal can also be helpful for > + metadata-intensive workloads. > > 2. Features > =========== -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
