This strategy uses multiple NetBackup policies to back up several clients once a day to the same destination volume.
Configuration: Five clients are to be backed up. Using multiple NetBackup policies (maximum of five), you specify that all five clients are backed up once a day to the same destination volume. You can schedule the policies to run at any time of the day, but the backups for all five clients are taken within a day.
Result: The results of this strategy are the same as that for Example 1: At the end of each day, one new Snapshot copy is created that contains a backup of each of the five clients. After five days, 25 unique backups to 5 clients are backed up in 5 Snapshot copies. Visually, this appears as the following table:
| Archival Snapshot copy | Contains... |
|---|---|
| snapshot1—day 1 | client1, client2, client3, client4, client5 |
| snapshot2—day 2 | client1, client2, client3, client4, client5 |
| snapshot3—day 3 | client1, client2, client3, client4, client5 |
| snapshot4—day 4 | client1, client2, client3, client4, client5 |
| snapshot5—day 5 | client1, client2, client3, client4, client5 |
Maximum number of backups preserved in the volume: Using this strategy, 250 Snapshot copies or 250 backups to each client—one backup of each client in each Snapshot copy—is reached in 250 days.
Expiring backups to remove the oldest Snapshot copies: Because 250 Snapshot copies is the recommended maximum, you should expire (delete) the oldest backup to each of the five clients from NetBackup after day 250. This deletes the first Snapshot copy, reducing the total number of Snapshot copies to 249. Now, you can take yet another backup for each of the five clients and save them in a subsequent Snapshot copy. After day 250, you must expire the oldest backup of each of the five clients daily to have a Snapshot copy available for future backups.
The retention period for each client backup cannot exceed 250 days so as not to exceed the maximum number of Snapshot copies allowed per volume.