For some reason we have not had any performance problems, especially
after upgrading to 2.0.16. Our config is described at
http://asg.web.cmu.edu/cyrus/config.html.
We consistently saw over 3000 imapds during the summer and now we are
typically seeing around 5500 imapds. (This also doesn't count imaps
connections, pop connections and other crap). Things still seem fine.
We do have multiple IO channels (the machine has something like 3 of
the dual channel PCI ethernet cards) and our RAID units are hardware
RAID units with 128MB of writeback/read cache in support of the RAID
units.
We are still planning on deploying the aggregator before the end of
this semester but the performance tweaks in 2.0.16 has made this less
urgent for us.
Other than the issue of the RAID unit, you clearly have more CPU power
and an equivalent amount of memory so I would look at the I/O
subsystem. Specifically, increase the number of I/O channels or the
raw speed. You may also want to look at doc/perf.html in the
distribution for more hints or tips.
Walter
