best filesystem for imap server

[Jim Miller]

> This is interesting because I have a linux box (RedHat AS3) using
> RAID 10.  I
> have some 5000 user accounts and anywhere from 2500 to 3000
> concurrent IMAP
> sessions -- I think the Mulberry client opens multiple sessions since it's
> only some 300 to 500 individual concurrent users.  Anyway, what I
> especially
> notice is that when the mail delivery queue on the MTA gets very
> large, which
> happens occassionally, the CPU load average goes way up and iowait time as
> displayed using top can exceed 300% on a four processor box and
> performance
> goes all to heck.  Is switching the filesystem to XFS likely to help this
> situation?  Since there is some 80GB of mail spool currently in use,
> switching the filesystem to XFS is not a simple task and I don't
> won't to do
> it on a lark.
>
> Thanks,
> Rob
>



I feel that XFS is a bad choice since it is not a 'truly' journaled file
system.  If you have a power failure/system crash/lockup, etc., etc. You
could very easily end up with a corrupt file system -- XFS doesn't write out
to the disks immediately (caching unwritten data to memory).  EXT3 is
journaled but very slow.  ReiserFS is a better choice for a journaled file
system and if you can hold off until all the bugs are worked out, Reiser4FS
would be the best choice (IMHO).


Jim


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