Simple Retention Policy

A simple retention policy scheme is intended for short-time archiving. When you specify retention policy settings for a simple scheme, you define how many restore points you want to retain on the target backup repository.

With the simple retention policy scheme, Veeam Backup & Replication creates a chain of restore points that subsequently follow one another. The first restore point in the chain is always a full backup (also known as recent full backup). All other restore points in the chain are incremental backups. By default, Veeam Backup & Replication keeps 7 restore points on the target backup repository.

To maintain a desired number of restore points in the backup chain, Veeam Backup & Replication uses the following rotation scheme:

1. During the first synchronization interval, Veeam Backup & Replication copies the first restore point — full backup — to the target backup repository.
2. During every next synchronization interval, Veeam Backup & Replication adds a new restore point — incremental backup — to the backup chain on the target backup repository. This happens until the number of restore points in the backup chain reaches the number specified in the retention policy settings.
3. After the new restore point is added, the allowed number of restore point is exceeded. Veeam Backup & Replication transforms the backup chain to make room for the most recent restore point.

The backup chain transformation is performed in the following way:

1. Veeam Backup & Replication re-builds the full backup file to include changes from the incremental backup following the full backup. More specifically, Veeam Backup & Replication injects data blocks from the first incremental backup in the chain into the full backup. This way, the full backup ‘moves’ one step forward in the backup chain.

2. The first incremental backup is removed from the chain as redundant. Its data has already been injected into the full backup, and so the full backup file contains the same data as this incremental backup.

For example, you want the backup copy job to keep 7 restore points. The synchronization interval is 1 day; the backup copy job starts on Sunday.

1. During the first synchronization interval on Sunday, Veeam Backup & Replication creates the first restore point — a full backup. Monday through Saturday Veeam Backup & Replication adds six incremental backups to the chain.
2. The next Sunday, Veeam Backup & Replication adds a new incremental backup to the backup chain. The number of allowed restore point in the backup chain is exceeded.

For this reason, Veeam Backup & Replication transforms the backup chain in the following way:

1. Veeam Backup & Replication merges data blocks from the incremental backup copied on Monday into the full backup copied on Sunday. This way, the full backup file ‘moves’ one step forward — from Sunday to Monday.

2. The incremental backup copied on Monday becomes redundant and is removed from the chain.

As a result, you have a chain of a full backup as of Monday and six incremental backups Tuesday through Sunday.