JFS vs EXT3 vs XFS vs ReiserFS

[Rashkae]

Res wrote:
> On Tue, 29 Apr 2008, Rashkae wrote:
> 
>> ReiserFS is supposed to be the fastest with small files.  I call
>> poppycock on that one.. ReiserFS is only fast in Namesys benchmarks.
> 
> 
> We have a mailstore, using vpopmail so its maildir, we did comparison 
> tests between ext2, ext3 and reiserfs, the same data, as the test box 
> grabbed the mail from our nightly rsync backup and sent it to and 
> from another dummy server, so we knew it would always be the same data,
> ext2 and ext3 performed the same speedwise, ext3 recovered faster for
> obvious reasons from a deliberate hard power-off, the rsync for ext2 and 3 
> took around 1 hour 40mins, for reiserfs the rsync from took 18 mins, and 
> send, it took about 1 hour 25 mins, so it has marginal write performance 
> but huge read performances,
> 

Your test case in this instance is a bit of a fluke... The read
performance for Reiser (and ext3 with dir_index option) is *very*
dependent on the order the files were written in.  If the files get
written to the disk in the same order as the file system hash algorithm
would produce, you get full speed read performance on either system...

Here's an example... configure mutt to store mail in a maidir location.
 then use mutt to copy gigantic quantities of messages into the mail
store. You need to copy enough mail that reading the entire directory
will exhaust your file cache.  You may want to reduce ram for this test.
Once all the mail is written, close mutt.  Now try to use tar to create
a backup of the maidir folder.  You should notice a very slow filesystem
IO, somewhere in the area of 1 to 2 MiB/s.  Once the backup is complete,
delete the maildir, then restore it from your tar file.  Create a tar
backup again... This time, your file IO should be well over 20 MiB/S.

The reason is that the first time, tar stored the files in the same
order as the file system hash order, and when the tar file was restored,
the files got written to disk in that same order as well.  This
performance boost will quickly degrade once you start using the system
however.  XFS and JFS don't suffer near the same performance penalties
and will maintain read performance for the entire directory over time.