Retention Policy for Quick Backups
When you perform quick backup, Veeam Backup & Replication creates a single VM incremental restore point. Unlike a regular incremental restore point that contains data for all VMs in a job, single VM incremental restore point contains data only for a specific VM.
A single VM restore point is not regarded as full-fledged restore point in the backup chain. From the retention policy perspective, single VM restore point is grouped with a regular restore point following it. When Veeam Backup & Replication needs to delete a single VM restore point by retention, it waits for the next regular restore point to expire — that is, Veeam Backup & Replication increases the retention by one restore point for some time. After the next regular restore point expires, Veeam Backup & Replication deletes two restore points at once.
If the backup chain is stored in a repository with the Use per-machine backup files option enabled, the retention increases in a different way. As a rule, the retention increases by the number of VMs from this chain for which quick backup was performed. This applies to the reverse incremental and forward incremental backup chains.