The server default policy enables client nodes to back up data to disk storage pools on the server. As an alternative, you can configure a policy to store client data directly in tape storage pools to reduce contention for disk resources.
If you back up directly to tape, the number of clients that can back up data at the same time is equal to the number of drives available to the storage pool (through the mount limit of the device class). For example, if you have one drive, only one client at a time can back up data.
The direct-to-tape backup eliminates the need to migrate data from disk to tape. However, performance of tape drives is often lower when backing up directly to tape than when backing up to disk and then migrating to tape. Backing up data directly to tape usually means more starting and stopping of the tape drive. Backing up to disk then migrating to tape usually means the tape drive moves more continuously, meaning better performance.
At the server command line, you can define a new policy domain that enables client nodes to back up or archive data directly to tape storage pools. For example, you can define a policy domain named DIR2TAPE with the following steps: