Retention Policy for Backups

For image-level backups, you can specify retention policy in days or restore points. Veeam Backup for Nutanix AHV retains the number of latest restore points defined in job scheduling settings as described in section Creating Backup Jobs. For backup chains created by jobs without scheduled active or synthetic full backups, Veeam Backup for Nutanix AHV applies forever forward incremental backup retention policy. For backup chains created by jobs that regularly produce active or synthetic full backups, Veeam Backup for Nutanix AHV applies forward incremental backup retention policy.

Forever Forward Incremental Backup Retention Policy

To track and remove redundant restore points from a forever forward incremental backup chain, Veeam Backup for Nutanix AHV performs the following actions at the end of each backup session:

1. Veeam Backup for Nutanix AHV checks the configuration database to detect backup chains that contain redundant restore points:

• If retention policy is specified in days, Veeam Backup for Nutanix AHV detects backup chains with restore points that are older than the specified time limit.
• If retention policy is specified in restore points, Veeam Backup for Nutanix AHV detects backup chains where the number of allowed restore points is exceeded.

2. If a redundant restore point exists in a backup chain, Veeam Backup for Nutanix AHV transforms the backup chain in the following way:

1. Rebuilds the full backup to include there data of the incremental backup that follows the full backup. To do that, Veeam Backup for Nutanix AHV injects into the full backup data blocks from the earliest incremental backup in the chain. This way, the full backup ‘moves’ forward in the standard backup chain.

2. Removes the earliest incremental backup from the chain as redundant — this data has already been injected into the full backup.

3. Veeam Backup for Nutanix AHV repeats step 2 for all other redundant restore points found in the backup chain until all the restore points are removed. As data from multiple restore points is injected into the rebuilt full backup, Veeam Backup for Nutanix AHV ensures that the backup chain is not broken and that you will be able to recover your data when needed.

Forward Incremental Backup Retention Policy

To track and remove redundant restore points from a forward incremental backup chain, Veeam Backup for Nutanix AHV performs the following actions at the end of each backup session:

1. Veeam Backup for Nutanix AHV checks the configuration database to detect forward incremental backup chains where a new full backup has been created (which starts a new backup chain fragment).
2. Veeam Backup for Nutanix AHV checks the following:

• If retention policy is specified in days, Veeam Backup for Nutanix AHV checks whether the period to keep restore points in the new chain fragment has reached the allowed time limit.
• If retention policy is specified in restore points, Veeam Backup for Nutanix AHV checks whether the number of restore points in the new chain fragment has reached the number of allowed restore points.

3. If the new backup chain fragment has reached the limit of allowed restore points, Veeam Backup for Nutanix AHV removes all restore points of the older backup chain fragment.