[ On Thursday, April 28, 2005 at 10:36:59 (+0200), Hamish Whittal wrote: ]
> Subject: [exim] IMAP server recommendations
>
> I have been using Cyrus Imap for some time now and it seems awfully
> slow.
The Cyrus IMAP server is not slow in any way. In fact it's just about
as efficient and fast as they get (though as mentioned it does still
have room for improvement, but those issues are almost certainly _not_
the cause of your problems).
Your server might be slow -- inappropriately sized or mis-configured.
I expect to be able to easily handle 50,000 heavy-use (broadband) users
on a single mid-sized DEC-Alpha based system I recently brought into
production for a client. The total hardware cost was well under
$40,000[cad], and had we trusted the OS support on more modern Opteron
or even Sparc64 systems the price might even have been as much as
$10,000 less (the FC storage array was $15,000 all by itself though and
that won't get any cheaper, just bigger :-). That same machine also
serves personal web pages for all those users too. Any current
Intel/AMD based server with a decent storage subsystem and enough RAM
can handle 25,000 IMAP users without even breaking a sweat, though
you'll obviously want to offload any stupidly-expensive filtering, such
as "virus" scanners to separate machine(s).
Your Cyrus setup might be mis-configured too (wrong mailboxes or quota
database types, etc.) As others have said you need to use "skiplist",
but not just for the mboxlist_db, but also for the quota_db and the
seenstate_db.
--
Greg A. Woods
H:+1 416 218-0098 W:+1 416 489-5852 x122 VE3TCP RoboHack <woods@???>
Planix, Inc. <woods@???> Secrets of the Weird <woods@???>
