Tuning Suggestions

[John Straiton]

Funny that I haven't found much in the lines of tuning suggestions for
Cyrus on googlegroups or in the info-cyrus archives but I think I may be
in need of it. I'm using a 4.8-STABLE FreeBSD machine, Dual 600Mhz with
1.5GB of RAM and plenty of RAID5 space.

We use Cyrus+Postfix+AMAVISd+SpamAssassin and are rather happy with the
combination. Our postfix feeds 5K addresses into 4K cyrus mailboxes.
Load on the machine usually rides between 0.5 and 1.0. top normally
reports around 60%-70% idle levels. In normal operations, I'll see
around 30-50 connections to the server at all times since most of our
users use pop3. We also limit mailboxes to no more than 25MB other than
employees. All employees use IMAP tho'. Our entire message store only
contains 5.6GB of messages.

The problem I'm having started about 2 days ago when our Nagios
monitoring started reporting that connectivity to the server (pop3/imap)
was failing. Then we'd get recovery notifications immediately after.
Kinda like the server was only unable to handle itself for a brief
moment and then would get back to business. I also personally noticed
that I'd get notifications in Outlook that some of the 5 IMAP
connections I keep to the server would time out periodically. I would
assume since send/receives occur every 5 minutes that these are not idle
timeouts.

This has never been a problem before, but obviously with a company
that's still growing, every day we have more users on the system than
the day before. I fear that something on the machine or in cyrus'
configuration is holding us back.

I come seeing suggestions for things I could check or change in order to
resolve this before it gets to being more of a problem than it is. I
figured I'd start with Cyrus and then move down to the OS level.

Thanks,
John Straiton
jks at clickcom.com
Clickcom, Inc
704-365-9970x101