Once a storage lifecycle policy is configured, it runs according to a single configuration or definition. The definition affects both the backups once they begin to run as well as the duplication jobs once the image is in process.

The ability to create storage lifecycle policy versions lets administrators safely modify a definition without waiting until all images that are associated with the storage lifecycle policy have been fully processed.

Each image that a storage lifecycle policy manages is tagged with the storage lifecycle policy name and the storage lifecycle policy version number. These two attributes are written into the image header, in the NetBackup image catalog.

Whenever an administrator creates or changes a storage lifecycle policy, NetBackup creates a new version (between 0 and n). New backup jobs use the most recent version.

When a new backup job is submitted to the Activity Monitor, the backup is tagged with the most recent storage lifecycle policy version number. The processing of an image that is associated with a version remains fixed according to that version of the storage lifecycle policy definition. It is fixed at backup time and does not change, unless the administrator uses the nbstl command to modify an existing version. Whenever the storage lifecycle policy is modified using the NetBackup Administration Console or bpadm, a new version is created.

A storage lifecycle policy version remains as long as there are any incomplete images that refer to the version.