Thoughts about storage

[Tom Golson <tgolson@tamu.edu>]

So, Texas A&M is coming up on it's one-year anniversary of running
Zimbra in production, and my thoughts are being turned to raising quotas.

We are running iSCSI against a pair of IBM-branded (N5500) NetApp
controllers.  Whatever the previous generation of the 3070 was.  All of
our drives are 10k rpm, 300 GB.  It is with extreme infrequency that I
see either controller turn more than 1,500 IOPS, or more than 30 MB/s of
combined I/O.

For backups, we acquired (a while ago) a Sun x4500 "Thumper" with about
27 TB of storage.  The threshold of pain associated with running linux
on that was unimaginable so we ran Solaris 10 for x86 and ZFS.  That was
a combination that never worked for backups; the NFS performance was
incredibly slow and resisted all efforts at tuning.  Last month, though,
we converted the machine to OpenSolaris with ZFS and, with a bare
minimum of tuning, we are now seeing very nice NFS performance and are
running backups to the x4500.

The remarkable improvement in NFS and (from testing on a similarly
configured, but different machine) iSCSI going from Solaris 10 to
OpenSolaris has got me looking at Sun's new 7xxx unified storage
appliances.  It's behavior is very NetApp-like, and the price is
unbelievably competitive.

Given that I see very comparable performance for NFS on the x4500 as I
see for iSCSI on the N5500, and the dizzying array of "enterprise" data
protection features in ZFS, I'm attracted to the idea of using the Sun
unified storage appliance and NFS to add storage for new mailbox
volumes.  The index and database volumes would stay on the filers, so
does anyone think this would be suicidal or is anyone using NFS for
mailbox volumes?

We do deliver about 300,000 messages/day to the Zimbra complex, with
around 6,500 concurrent mail readers (web and IMAP sessions) during peak
usage.  iSCSI against the Sun storage appliances is certainly an option,
so comments about whether anyone else has looked at the unified storage
appliances in general would be appreciated also.  Thanks!

--
Tom Golson
Chief Systems Engineer
Open Systems Group
Computing and Information Services
Texas A&M University