Design for a largish Cyrus server

[Gary Mills]

Our current SMTP and IMAP server is a Sun V480 with 4 CPUs and 16 GB
of memory.  It's running Solaris 9.  It has 300 GB of IMAP storage on
two 12-disk hardware RAID arrays.  This contains about 30,000
mailboxes.  There are about 1200 simultaneous IMAP sessions at the
busiest time of the day.  It's performing quite nicely, but we will
soon need to expand the IMAP storage considerably.  Here's what I have
in mind.  Comments or suggestions are welcome.

I'd like to leave SMTP on the V480 and add a 2-node load-balancing
cluster for IMAP.  Each of the two servers would be a Sun V440 with 4
CPUs and 16 GB of memory.  They would run Solaris 10.  Sun's QFS would
provide shared storage from an iSCSI SAN.  There would be 3 TB of
storage on the SAN.  Daily backup and restore would be from snapshots
on the storage device.  We'd use Legato Networker for longer-term
backup and restore.

Is anyone else running Cyrus on a load-balancing cluster?  Is anyone
else using QFS with Cyrus?  What about iSCSI storage?  What's
practical for backup and restore with 3 TB of IMAP mailboxes?

-- 
-Gary Mills-    -Unix Support-    -U of M Academic Computing and Networking-