Capacity managed retention type for SLP operations
A Capacity managed operation means that NetBackup automatically manages the space on the storage, based on the High water mark setting for each volume. Capacity managed is not available to tape storage units since tape capacity is considered to be infinite.
The High water mark and Low water mark settings on the disk storage unit or disk pool determine how the space is managed.
See High water mark storage unit setting.
See Low water mark storage unit setting.
An image copy with a Capacity Managed retention is not eligible for expiration until its dependent copies have been created.
If space is needed for new images, NetBackup removes expired backup images from a capacity-managed disk volume in two passes, as follows:
Pass one | NetBackup removes any backup images that are past the Desired cache period setting. NetBackup removes images until the low water mark is reached or all images that are past the Desired cache period are removed. |
Pass two | Pass two processing is initiated if the outcome of the pass one processing is one of the following:
NetBackup removes images until the low water mark is reached or all images that are not past the Desired cache period are removed. An image may be deleted if it has not been duplicated for all operations in a storage lifecycle policy. If the operating system time is past the date that matches the longest retention period for an image, the image is eligible for deletion. |
To see exactly when the storage reaches the low water mark value is difficult. A backup can occur at the same time as the expiration process occurs. After the backup is complete, the low water mark may be slightly greater than its lowest possible value.
The retention period for capacity managed storage is not assured as it is for a fixed retention period. The Desired cache period becomes a target that NetBackup tries to maintain. If the space is not required, the backup data could remain on the storage longer than the Desired cache period indicates.