Backup set retention

When you plan your SnapManager backup schedules, you also need to manage the number of Snapshot copy-based backup sets that are retained online.

You can do the following to manage the number of backup sets kept online:

• Regulate the number of Snapshot copies per volume.
• Delete old and unnecessary backups.
• Specify a backup deletion criteria that deletes the oldest backups for each Storage Group and backup management group.
• Explicitly delete any backups or Snapshot copies of LUNs created during a restore operation.

• Maximum number of Snapshot copies per volume
  The Data ONTAP software used with SnapManager supports a maximum of 255 Snapshot copies per volume, including copies not created by SnapManager. Because each SnapManager backup operation creates Snapshot copies, a SnapManager backup operation fails if the volume that contains the database LUN exceeds the 255 Snapshot copy capacity.
• Ways to delete Snapshot copies
  To avoid reaching the limit of 255 Snapshot copies per volume, delete your old SnapManager backups when they are no longer needed.
• Automatic deletion of Snapshot copies
  You can manage the number of Snapshot copies you store by configuring SnapManager to delete backups automatically, based on how old the backups are or based on how many of them are stored.