Availability database backup operations

Data Protection for SQL Server backs up each availability database as a single object, regardless of which availability replica is used for backup and restore operations.

An AlwaysOn Availability Group (AAG) requires SQL Server instances on Windows Failover Cluster nodes. An availability group can have a number of replicas. For example, availability group 1 might have replicas node1, node2, and node3.

A cluster node might be a replica for one or more availability groups. For example, node1 might be a replica for availability group 1 and another availability group.

The AlwaysOn Node is used to manage backups of availability databases. When you work in a Tivoli Storage Manager environment, the AlwaysOn Node is to be common in a Windows Failover Cluster. This presence enables the management of backups of an availability database in a single location, regardless of the replica that is used to complete the backup.

You can run the following types of VSS backup operations:
  • Full VSS backups of the primary availability replica
  • VSS copy-only full backups of availability replicas
You can run the folowing type of legacy backup operations:
  • On the primary replica, legacy full, differential, file, set, group, and log backups
  • On the secondary replica, legacy full, file, set, group, and log backups
  • VSS and legacy copy-only full backups, legacy copy-only file, set, or group backups, and legacy copy-only and normal log backups
Restriction: Microsoft does not support legacy full backups on secondary replicas. Data Protection for SQL Server, however, does permit you to run a full backup of a secondary replica based on Tivoli® Storage Manager policy.

When you run a full legacy backup of a secondary replica, the underlying implementation of Data Protection for SQL Server is to back up the data as copyfull. However, Data Protection for SQL Server detects the intended full backup operation and applies the Tivoli Storage Manager policy that is associated with the full backup type.

Microsoft Management Console (MMC) and CLI views honor the Tivoli Storage Manager policy that applies to the backup type and in this instance, show the backup type as full. For more information, see Active Secondaries: Backup on Secondary Replicas (AlwaysOn Availability Groups).

For all backup operations of secondary availability replicas, the secondary replicas must be in the synchronized or synchronizing state.

To assist you with scheduling and load balancing, scheduled backup preference settings of availability groups are also available.