The following backup copy group parameters significantly influence your backup policy:

Determines the maximum number of Exchange Server database backup versions to retain for the databases that exist on the protected Exchange Server system.

Determines the maximum number of Exchange Server database backup versions to retain for the databases that were deleted from the protected Exchange Server system after they were backed up by IBM Spectrum Protect.

The VERDeleted copy group parameter can control both differential and incremental backups. In the case of differential backups, the VERDeleted parameter applies when a new full backup is done (which deactivates an active differential backup) until the next differential backup is done. To maintain consistent version-expiration behavior, you can set the VERDeleted and VERExists parameters to the same value in the management class used for differential backups.

Note: If you set the VERDeleted parameter to nolimit, the expiration of backup versions is controlled instead by the time-based retention parameters RETExtra and RETOnly.

Determines the number of days to retain an Exchange Server database backup version after that version becomes inactive.

Determines the number of days to retain the last Exchange Server database backup version of a database that was deleted from the protected Exchange Server system.

The RETOnly parameter applies to all backup types, including incremental backup objects that can never have more than one version because they are always uniquely named with a unique time stamp. However, all legacy backup objects for an Exchange Server database are deactivated when a new full backup of that Exchange Server database is completed. VSS backup objects remain active.

The retention period that is set in the RETOnly parameter controls the expiration of incremental backup objects. When you set the value of the RETOnly parameter for incremental backups, the value must be, at a minimum, as long as the value that is set for the full backup on which the incremental backup depends. You can use the same management class for incremental backups and the full backup objects (that are retained the longest) to ensure that an adequate value is used. However, when a new legacy full backup of that Exchange Server database is completed, all legacy backup objects for an Exchange Server database are deactivated. In this scenario, VSS backup objects remain active.