An availability group fails over at the level of an availability replica. which hosts the primary databases, and one to eight secondary replicas, each of which hosts a set of secondary databases and serves as a potential failover targets for the availability group. Two types of availability replicas exist: a single primary replica. For more information, see Active Secondaries: Backup on Secondary Replicas (Always On Availability Groups).Įach set of availability database is hosted by an availability replica. Alternatively, you can create log backups and copy-only full backups of secondary databases. You can create any type of backup of a primary database. Continue to back up your databases and their transaction logs on a regular basis. An availability group supports one set of primary databases and one to eight sets of corresponding secondary databases.

A read-scale availability group is a group of databases that are copied to other instances of SQL Server for read-only workload.

An HA availability group is a group of databases that fail over together. You can create an availability group for high availability (HA) or for read-scale. For a summary of the benefits offered by availability groups and an overview of Always On availability groups terminology, see Always On Availability Groups (SQL Server).Īn availability group supports a replicated environment for a discrete set of user databases, known as availability databases. This article introduces the Always On availability groups concepts that are central for configuring and managing one or more availability groups in SQL Server.

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