Note This functionality is not available in the Standard editions of the Cyber Protection service.
SQL Server high-availability solutions overview
The Windows Server Failover Clustering (WSFC) functionality enables you to configure a highly available SQL Server through redundancy at the instance level (Failover Cluster Instance, FCI) or at the database level (AlwaysOn Availability Group, AAG). You can also combine both methods.
In a Failover Cluster Instance, SQL databases are located on a shared storage. This storage can only be accessed from the active cluster node. If the active node fails, a failover occurs and a different node becomes active.
In an availability group, each database replica resides on a different node. If the primary replica becomes not available, a secondary replica residing on a different node is assigned the primary role.
Thus, the clusters are already serving as a disaster recovery solution themselves. However, there might be cases when the clusters cannot provide data protection: for example, in case of a database logical corruption, or when the entire cluster is down. Also cluster solutions do not protect from harmful content changes, as they usually immediately replicate to all cluster nodes.
Supported cluster configurations
This backup software supports only the Always On Availability Group (AAG) for SQL Server 2012 or later. Other cluster configurations, such as Failover Cluster Instances, database mirroring, and log shipping are not supported.
How many agents are required for cluster data backup and recovery?
For successful data backup and recovery of a cluster Agent for SQL has to be installed on each node of the WSFC cluster.
Backing up databases included in an AAG
Tip After you install the agent on one of the nodes, the software displays the AAG and its nodes under Devices > Microsoft SQL > Databases. To install Agents for SQL on the rest of the nodes, select the AAG, click Details, and then click Install agent next to each of the nodes.
Important You must select the AAG itself, rather than the individual nodes or databases inside of it. If you select individual items inside the AAG, the backup will not be cluster-aware and only the selected copies of the items will be backed up.
Recovery of databases included in an AAG
When you select a clustered database under Devices > Microsoft SQL > Databases, and then click Recover, the software shows only the recovery points that correspond to the times when the selected copy of the database was backed up.
The easiest way to view all recovery points of a clustered database is to select the backup of the entire AAG on the Backup storage tab. The names of AAG backups are based on the following template: <AAG name> - <protection plan name> and have a special icon.
The software automatically defines a cluster node to which the data will be recovered. The node's name is displayed in the Recover to field. You can manually change the target node.
Important A database that is included in an Always On Availability Group cannot be overwritten during a recovery because Microsoft SQL Server prohibits this. You need to exclude the target database from the AAG before the recovery. Or, just recover the database as a new non-AAG one. When the recovery is completed, you can reconstruct the original AAG configuration.