[KLUG Members] Qmail-ldap + netapp results

[Adam bultman]

Good afternoon, KLUGgers.

I've recently completed the finished 'cluster' setup of qmail+ldap and a
network appliance.

By and large, the slower 800 MHz servers make GREAT smtp servers, and
with the network appliance, they are able to more than reliably and
quickly deliver mail.  I've been able to get them to back up a bit by
pumping them with 20,000 messages (slowdowns aided by heavy logging on
the blade with the ldap server) but they'll crank through the messages
reliably and quickly.  Besides- SMTP isn't instantaneous - you don't get
users complaining if it takes a few extra minutes to deliver a piece of
mail.  Having multiple servers handle mail complicates debugging a bit,
but it spreads out load and gives a bit more protection in the case of a
failure (i.e. no total blackout).

IMAP is another story; the low amount of RAM and the slow processor
speed causes IMAP to be a bit pokey when you have a large mailbox. I can
only assume that of the users there are using the current mailserver,
there's got to be a lot of people with large mailboxes.  I installed
courier-imap-ldap on a spare Xeon box (dual 2.66 GHz) and forwarded a
port over SSH, and things went much more smoothly, hardly touching the
processor.  Throwing more slow systems at IMAP won't fix the problem,
but throwing a couple fast ones will. 

In the end, qmail-ldap is unbelievably cool.  A bit more functionality
in phpLDAPadmin would be nice, but isn't vital.  We do all our LDAP
admin through the command line and ldif files anyway.  If we deploy for
everybody, we'll probably write a wobject for webGUI and have that done
anyway.     The Netapp makes deploying new imap+pop and smtp servers a
cinch.  Courier-IMAP could do with some caching like cyrus does, but you
can't have everything.  The sky didn't fall like some people predicted,
although it drizzled at times.

Adam