Mail delays--temporarily solved

In the last week or so, our Tiger (v10.4.11) mail server has really slowed down delivery of its mail. I tried putting in more RAM (now at 1.5 GB) to no avail on our G4 867 PowerMac.

We have about 20 IMAP users and 10 POP users.

It appears that mail is not being processed fast enough by the built-in virus and spam checkers. And Activity Monitor tells me that the CPU is constantly at 100% usage. Thus, mail stacks up in the queue (up to as many as 300 messages to be delivered) with two-hour delivery delays while 30 users pound on the mail server for new mail.

...We had been seeing CPU use maxed out constantly, with two processes for clamAV each accounting for 40+% of the CPU usage. I tried stopping virus and junk scanning earlier, but that seemed to stop the mail queue entirely (perhaps I failed to restart or something).

So, as a short-term fix, we turned off virus scanning and spam filtering on the mail server last weekend (correctly, it appears). Doing so seems to have returned the delivery of messages to their earlier level of speed.

I'm not sure what triggered the sudden delivery delay a couple of weeks ago. But the server was spending inordinate amounts of time filtering and scanning mail rather than delivering it.

Medium-term, we'll either do an upgrade to Leopard or update 10.4.11 to have newer versions of clamAV and clamd, which I believe may solve the problem.

HTH someone.