Slow lmtpd

[Andre Nathan]

On Tue, 2007-03-06 at 08:57 -0500, John Madden wrote:
> Are you connecting to lmtpd over TCP or something?  I haven't seen this
> behavior with Postfix and a UNIX socket, at least.  But still, I'd
> rather have Postfix defer the connection than have huge IO wait
> queues.  ...If nothing else, think about what that's doing to your IMAP
> clients. :)

Yep, TCP. I should have mentioned that.

> Ah, it sounds here like you're connecting multiple SMTP frontends to a
> single lmtpd backend?  Sorry if I missed that earlier.  FWIW, I'd stick
> postfix on this box to handle the incoming mail and do all that over
> SMTP, then deliver over LMTP to Cyrus locally and over a unix socket.
> SMTP ought to prove more reliable than LMTP over a network, IMO.  This
> has the added benefit of only having to tweak one Postfix install for
> its delivery to lmtpd!

Hmm, I never thought of having two "layers" of MTAs like this. I'll add
it to the list of things to try.

> I think you'd be better off with smaller disk sets for different I/O
> patterns.  Like a 2-disk RAID-1 for /var/lib/imap and the rest striped
> for /var/spool/imap, etc.  Either way, you want to separate not just on
> LVM, but on the physical spindles doing the work.

I could try that for later systems (changing the raid config on the
current one is not possible without moving everything to another
machine). The thing about this solution that I don't like is
that /var/lib/imap is only ~300MB here, so it would waste a lot of disk
space. But then, maybe that's a small price I'd have to pay.

Thanks,
Andre