 Performance
I see 3 mysqld groupings - are you running another DB besides the message store and logger instances?
I think I asked the IOWAIT question incorrectly - what I was after is what percentage of processes (as reported by top) are in the iowait state?
It's hard to tell if they're backing up before or after amavis - but if amavis is eating a large amount of CPU, they're probably backing up before it.
Couple of things to try to narrow this down:
1 - Run a test that just blasts mail into the system - no delay between sends, multiple processes sending mail to multiple accounts at the same time. Load up the queues, stop sending, and watch what the server does as the queues drain - this will eliminate the variables in the send delay, etc.
2 - check the postfix logs, look for delay=<num> - this will tell you how long it takes postfix to deliver a message. Each message takes 2 hops: postfix->amavis->postfix (via smtp) and postfix->mailstore (via lmtp). Which delay is higher?
3 - turn of amavis - you can do this in the admin console, which should cut the amavis step out of the delivery process. This will tell us where things are slowing down.  |