Matt Simonsen <[EMAIL PROTECTED]> writes:
> We have a qmail server with only 15 users on it, Qmail 1.03, Red Hat
> 7.0, no patches. Due to several shared IMAP accounts with 5k-7k
> messages which are checked regularly we are having the IMAP server
> essentially quit responding throughout the day. I believe this is due
> to the EXT2 file system not handling the number of messages in the
> maildirs, my current understanding leads me to the idea of moving only
> the /home partition where the Maildirs are located to ReiserFS. I
> don't really understand the intracacies of all the patches listed at
> www.jedi.claranet.fr/qmail-tuning.html - what I am hoping is that by
> only changing /home and not the queue/working directories I can not
> deal with any of the troubles listed that require optimization and
> patching. Would this work, or is there an issue in transfering mail
> from the queue to the Maildir?
>
> I don't want to break RFC standards, apply unneeded patches, or
> otherwise hurt our email server to fix a different problem. What other
> ways would you deal with this issue, that is other than having users
> remove/file their messages better?
reiserfs requires the exact same patch as ext2 does (the "qmail for
linux" patch). You'll want to mount it with the "notail" option if
you're using it for performance reasons. You should be able to mount
any filesystems you want with reiserfs.
This is much more likely to be server-related than filesystem related,
though...
Have you done any profiling or performance monitoring that indicates
that the problem is filesystem or disk related? What is the load on
the machine when the IMAP server stops responding? Does the whole
machine stop responding, or just the IMAP server? Does it stop
accepting new IMAP connections, or current ones freeze up?
What IMAP server are you using? What format are your mailboxes in?
If they're not in a Maildir, that's absolutely your problem; switch to
Maildir storage and courier-imap, and you'll see a nearly tenfold
performance improvement. If messages are in a Maildir, while you're
seeing the problem, if you go into the directory with the messages and
do an "ls -l" how long does it take to list all 5000+ messages? If
this runs fine, it's not the filesystem; scanning all messages does
essentially this. Try using strace on the IMAP server to see where
it's getting stuck; you might be surprised. Or, if you're not using
it, switch to courier-imap; it's the best performing IMAP server I've
seen.
You might want to check your logs for a disk problem, too; that would
explain the problems you're seeing.
Good luck,
----ScottG.
