Doing Cyrus *right* for a large installation

[Andrew Morgan]

I have an existing Cyrus installation consisting of:

(2) backend servers, each with 800GB of SAN storage, 1 cyrus partition
(3) frontend servers
(1) mupdate master

Obviously, we are running Cyrus as a murder cluster and we really like 
that.

I'm interested in upgrading both the servers and the storage for Cyrus, 
but I need some advice.

I would like to add a *lot* more storage so that we can increase our email 
quotas (currently 200MB per user).  It seems like the proper way to scale 
up is to split the Cyrus metadata off and use some large SATA drives for 
the message files.  I was considering adding a shelf of 1TB SATA drives to 
our SAN.  I could store the metadata on existing FC drives on the SAN, or 
just use internal disks on the servers.

But then I started thinking about how I was going to backup all this new 
data...  Our backup administrator isn't too excited about trying to backup 
12TB of email data.

What if we used Cyrus replication in combination with delayed expunge as a 
form of "backup"?  We currently only keep 1 month of daily backups 
anyways...

For those of you running large installations, how do you back them up?

Thanks,

 	Andy