This strategy uses a single NetBackup policy to back up several clients once a day to the same destination volume.
Configuration: Multiple Clients (client1 through client5). Using one policy, you specify that all five clients are backed up once a day to the same destination volume.
Result: At the end of each day, one new Snapshot copy is created that contains a backup of each of the five clients. For example, at the end of the first day, there will be one Snapshot copy containing the five backups, one for each client; at the end of the next day, there will be two Snapshot copies, the one from the first day and one new Snapshot copy containing another backup to each client; and so on. After five days, 25 unique backups to 5 clients are backed up in 5 Snapshot copies. Visually, this appears like the following table.
| Archival Snapshot copy | Contains... |
|---|---|
| snapshot1—day 1 | client1, client2, client3, client4, client5 |
| snapshot1—day 2 | client1, client2, client3, client4, client5 |
| snapshot1—day 3 | client1, client2, client3, client4, client5 |
| snapshot1—day 4 | client1, client2, client3, client4, client5 |
| snapshot1—day 5 | client1, client2, client3, client4, client5 |
Maximum number of backups preserved in the volume: Using this strategy, 250 Snapshot copies or 250 backups of 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 per volume, you should expire (delete) the oldest five backups (one of each client) from NetBackup after the 250th day. This deletes the first Snapshot copy, reducing the total number of Snapshot copies to 249. Now, you can take yet another backup of each of the five clients and save subsequent Snapshot copies. After day 250, you must expire the oldest backup for each client daily to have a Snapshot copy available for future updates to the five clients. The retention period for each client backup therefore cannot exceed 250 days to prevent the risk of exceeding the Snapshot copy limit for the volume.