[Dovecot] Highly Performance and Availability

[Wayne Thursby]

Thank you to everyone who has contributed to this thread, it has been
very educational.

Since my last post, I have had several meetings, including a conference
with Dell storage specialists. I have also gathered some metrics to beat
around.

The EqualLogic units we are looking at are the baseline models, the
PS4000E. We would get two of these with 16x1TB 7200RPM SATA drives and
dual controllers for a total for 4xGbE ports dedicated to iSCSI traffic.

I have sent the following information and questions to our Dell reps,
but I figured I'd solicit opinions from the group.

The two servers I'm worried about are our mail server (Postfix/Dovecot)
and our database server (PostgreSQL). Our mail server regularly (several
times an hour) hits 1 second spikes of 1400 IOPS in its current
configuration. Our database server runs aroun 100-200 IOPS during quiet
periods, and spikes up to 1200 IOPS randomly, but on average every 15
minutes.

With 4xGbE ports on the each EQL device, and also keeping in mind we'll
have two of those, is it reasonable to expect 1400 IOPS bursts? What if
both of these servers were on the same storage and required closer to
3000 IOPS?

--
Wayne Thursby
System Administrator
Physicians Group, LLC