How to manage consumption of Snapshot copies

The maximum number of Snapshot copies allowed by Data ONTAP is 255 for a volume; however, the recommended maximum number of Snapshot copies available for backups is 250, because other Data ONTAP services require Snapshot copies. You can use different strategies to optimize consumption of Snapshot copies.

When creating backup policies, you should carefully determine backup schedules, retention periods, and backup frequencies of the client-policy pairs directed to the same destination volume. This will maximize the number of backups stored in a given destination volume without the risk of running out of Snapshot copies.

In the following examples, multi-streaming is not used. The examples show different backup strategies that illustrate Snapshot copy optimization and the effects of backup schedules, retention periods, backup frequencies, and the use of FlexVol volumes.

• Example 1: One policy for multiple clients, one destination volume
  This strategy uses a single NetBackup policy to back up several clients once a day to the same destination volume.
• Example 2: Multiple policies for multiple clients, one destination volume
  This strategy uses multiple NetBackup policies to back up several clients once a day to the same destination volume.
• Example 3: Two policies, different schedules, multiple clients, one destination volume
  This strategy uses two NetBackup policies to back up two sets of clients to the same destination volume. One policy schedules backups once a day; the other policy schedules backups twice a day.
• Example 4: Two policies, different schedules, multiple destination FlexVol volumes
  This strategy uses two NetBackup policies to back up two sets of clients to two FlexVol volumes. One policy schedules backups once a day; the other policy schedules backups twice a day.