Backup Retention and Immutability

Veeam Data Cloud for Microsoft Azure stores backups in immutable storage. After data is backed up, no user can modify or delete it until the immutability period expires. This protects backups from accidental deletion, tampering, and ransomware.

Why Backups Can Outlive the Retention Period

For VM backups, the backup retention period that you configure in the SLA template defines how long you want to keep restore points. Because VM backups are immutable, restore points are not necessarily removed from storage on the day their retention period ends.

Veeam Data Cloud for Microsoft Azure extends the immutability period of VM backups in periods of up to 10 days, called block generations. All VM backups created within one generation share the same expiration date. As a result, a restore point can remain in storage for up to 10 days after its retention period ends. After the expiration date, outdated restore points are removed automatically.

You cannot shorten the immutability period of existing restore points. If you reduce the retention period in the backup policy settings, the change applies only to restore points created afterward.

Example

Consider a VM backup policy that creates a backup once a day starting from March 1 and keeps backups for 5 days.

• Backups created from March 1 to March 10 belong to the first generation. All of them expire on March 16, although the backup from March 1 would normally be removed on March 6.
• On March 11, a new generation starts. Backups of this generation expire on March 26.
• After March 16, the restore points of the first generation are removed.