When you need to restore that much of data quickly you'd think availability rather than DR so perhaps a cluster and/or replication could be an option. Generally speaking, a restore of catalog would need a lot of small files to be restored which is not an easy task logically for the file system and it may not be the easiest problem to solve. With 3TB in the catalog you might think of a domain split or replication. There are cheap solutions to replicate the catalog without a cluster if you are willing to do extra steps for restore/failover.
Many people in this thread suggesting AIR, this could be a valid option for future backups, however, if you have 3TB in the catalog, you might have quite a bit on tape storage with long retention for whose images AIR would not help at all. Also if copy of the policy database is also critical (and sometimes it is), AIR wouldn't help either.