We are running exim and noticed that mail was not working both in and out this morning. Went in to investigate in WHM and found over 3000 messages in the queue (about 1500-2000 being spam), some of the messages were 6 days old. We were able to remove the messages in the queue. But now we often see the server bogg down almost to a stop. We are able to SSH into the server and find exim running a few different processes taking up huge amounts of CPU time. I saw the server load become stable at 50 (yes 50.0) and saw it peak to over 70. Our server load has never been over 3 in the past.

We are able to check exims queue and there are only 3 or 4 messages in there, why is the server working so hard?

Eric

I wonder if you guys have specified the maximum amount of time the message can be in the queue/waiting to be delivered? 5 days are usually a good setting for SMTP servers...

ps. have you checked top and other process lists to see what bogs down your server?

Exim slows down mail transport when the load becomes to high... if your retry amount is to high or max time a email can set in the queue is to high, mail just piles up. Can always pile up due to spamming

Yep - most likely your load on the server stays high regardless of exim. Check the exim.conf, there's a setting for "max load" and whatever that load is, if your server is above it, exim will queue the email and not deliver it..which means if your server is overloaded, you need to adjust the maximum load.

Easy way I think, type /scripts/exim4 . If after updating it also - still the problems continues - nothing left without modifying exim configuration file.