[Dovecot] Recommended FS for Dovecot Maildir

[Les Mikesell]

On Tue, 2006-05-09 at 16:32, Wouter Van Hemel wrote:

> In real life on general purpose servers, the gains have been quite
> marginal, though. Filesystem change isn't a miracle cure for performance
> problems, obviously; if that's the problem, more disks to spread the
> transactions over make a much bigger difference I/O wise.

If you put a huge number of files in the same directory, the
filesystem type can make a big difference in access time.
Remember that before you can create a new file you must
scan the current list first to see if that name already
exists and the whole operation has to happen atomically with
the directory locked. Filesystems that index the directories
can help compared to a linear scan although there are some
tradeoffs.  Also some never shrink a directory when files
are removed so you continue to scan all the empty slots.

Long ago I used a benchmark program called 'postmark' to
test the speed of file creation/deletion operations that
are typical in maildir environments.  I haven't been able
to find it recently although the last time I mentioned it
someone said it was in the debian repositories and available
via apt-get.

-- 
  Les Mikesell
   lesmikesell at gmail.com