I've been looking at Zimbra again having been sidetracked for the past few months. I wrote a small perl script to simulate sending messages to about a dozen users on the system, message-size of 5 - 10k and sending messages every 2-3 seconds (sometimes that means two messages as once, sometimes none for 6 - 10 seconds).
Anyway - the system load became so high (30+) that I could barely run "uptime" or do anything else on the system. The test machine is an Athlon64 with 1gig of RAM running 32-bit CentOS4.2 (~RHEL4).
Is this remotely normal? This is with no-one actually reading their mail at the same time.
Java & amavisd seem to be the two processes I see at the top of "top" most often. I've tried with swap completely disabled and still get the same kind of load.