We also use Netapp. The snapshot feature is definitely worth using, and is very effective for any file restores. Very occasionaly I will need to go to tape, but only because we didn’t have enough disk space to cover as many versions as we might have wanted with the snapshots, or because it is easier to do a restore with our Tivoli Storage Manager options than with the shapshots.
You say your two filers are redundant, but you don’t say if they are in the same site, or at different ones. It is important to have tape (or VTL) backups in case of a disaster (fire, etc) if they are at the same location. If not, I would think you have enough protection. Or, if you want a solution that gives a little to each side of the arguement, you could use your backups as a disaster recovery, just keeping a week’s worth, etc.
CoxHealth, Springfield, MO