Performance scaling.

[Michael Bull]

(Sorry for the double post, I botched the subject line).

I'm looking to hear from other administrators of IMP, particularly those
running IMP+Apache+Postgres on how they've optimized their system to better
handle load.   Our web-mail service launch here at the University of Guelph
is now in it's first full year of production use, and we're getting almost
10,000 logins to webmail per day on our Sun E250 server; at the busy points
in the day, we're running 1000 process and the machine is 0% idle.

While I know there are documents on apache performance turning, I'm
interested to know from those that have already been there what they've
found most useful.  Thanks all!