We are having a devil of a time getting the Zimbra backup store copied to another device for DR purposes.
We run Veritas NetBackup 5.1 (yes, I know it's old) and have been unable to successfully run a backup. We run into a number of files limitation (or it could be a related memory issue) when NBU backs up the 500 Million files in the backup store (which contains four full backups and their incrementals). We have successfully run a raw backup that took forever to finish that sure makes it look like a number of files issue.
We have also copied (a la NDMP) one of the backup stores (we run a three node cluster, each with its own backup store) to our Data Domain box but do not have enough space currently to hold all three backup stores.

What do other institutions do regarding Disaster Recovery for Zimbra?