Symantec recommends that you use a NetBackup policy to produce multiple, original backup images. You should then use a Vault profile to eject and transfer one or more of the original images off site.
In most situations, vaulting originals has the following advantages:
Uses less drive-time than duplicating backup images from the original tapes. For example, a backup job that creates two originals of a backup image uses two drives: two units of drive time. Conversely, a backup job that creates one original image uses one drive, and a vault job that creates one duplicate of the original uses two drives: three units of drive time. Over time, duplicating backup images consumes more drive time than writing multiple originals during a backup job.
Avoids configuring for duplication. In complex environments (such as with multiple media servers, multiple robots, or multiple retention period requirements), it can be difficult to configure the duplication steps of Vault profiles. It is possible to send large amounts of data over the network without careful configuration, although in storage area network (SAN) environments network traffic may not be an issue.
Use VTL tapes. You can send your backups to VTL tapes with minimum retention period required for your recovery. You can then duplicate to physical tapes from VTL tapes and expire the VTL tape copy using the setting.