Usually a high load average means that a spamd child suddenly (or possibly
slowly) got fat, and you are out of memory and thrashing to beat the band.
The two most common causes of this seem to be Bayes expiry runs and Awl
expiry runs. Sometimes though it can seemingly happen from some unknown
sequence of mail messages.
How many children are you running? What is the max lifetime (messages
processed) per child? Limiting to probably 5 children, or maybe even less
in your case with so few users, and limiting to maybe 20-100 connections per
child will probably work around your problems.
Oh, I'm assuming you have at least 512M or so. If not, you might want to
cut down to only a couple of children, and definitely go with the lower
number of connections per child.
Loren
