The High water mark setting (default 98%) is a threshold that triggers the following actions:

• When an individual disk volume of the underlying storage reaches the High water mark, NetBackup considers the volume full. NetBackup chooses a different volume in the underlying storage to write backup images to.

• When all volumes in the underlying storage reach the High water mark, the BasicDisk storage is considered full. NetBackup fails any backup jobs that are assigned to a storage unit in which the underlying storage is full. NetBackup also does not assign new jobs to a BasicDisk storage unit in which the underlying storage is full.

• NetBackup begins image cleanup when a volume reaches the High water mark; image cleanup expires the images that are no longer valid. NetBackup again assigns jobs to the storage unit when image cleanup reduces any disk volume's capacity to less than the High water mark.

  If the storage unit is in a capacity-managed storage lifecycle policy, other factors affect image cleanup.

  See Capacity managed retention type for SLP operations.

For more information, see the following guides:

• NetBackup Deduplication Guide.

• NetBackup Administrator's Guide, Volume II.