Re: Zimbra capacity

[Rich Graves <rgraves@carleton.edu>]

There's a *lot* of variables that go into this, but 3000 users (1900 undergrad, rest fac/staff) on dual quad core (X5450) running ZCS 5.0.19 on RHEL 4.8 over Compellent FC SAN looks like:

http://mail.carleton.edu/charts/2009-10-28/

Incidentally, I tried UseConcMarkSweepGC as suggested at Performance_Tuning_Guidelines_for_Large_Deployments, but switched back to UseParallelGC after three incidences of severe stalls in the kernel, each causing 15 minutes of downtime. All CPU cores were 100% pegged in system, unable to process interrupts or keep time... and then they came back. I'd assume that the updated kernel in RHEL 5 and/or the updated Java in ZCS 6 would fix whatever weirdness I've run into. Zimbra Support helped me address my error contributing to the first outage, but had no ideas on the second and third.

Has anyone else done serious real-world comparison of UseParallelGC versus UseConcMarkSweepGC? In theory, the latter is much better, but it seems to have jinxed my server, so I backed off. Server was completely stable before trying UseConcMarkSweepGC and has been completely stable since.
-- 
Rich Graves http://claimid.com/rcgraves
Carleton.edu Sr UNIX and Security Admin
CMC135: 507-222-7079 Cell: 952-292-6529