What Are Always On availability Groups?

What is the difference between always on and availability groups?

AlwaysOn Availability Groups (AAG) provide high availability and disaster recovery at SQL database level. Data Protection for SQL Server protects availability databases in both AlwaysOn failover cluster instances and in an AAG. An AlwaysOn node manages backups of availability databases.

What is the difference between clustering and AlwaysOn?

The main difference is that a clustered instance has the same binaries installed and configured on two or mode cluster nodes (physical or virtual machines) and the database files are sitting on a shared disk.

What is availability mode in always on?

In Always On availability groups, the availability mode is a replica property that determines whether a given availability replica can run in synchronous-commit mode.

What are the restrictions on availability groups?

Restrictions (Availability Groups) Unique availability group name: Each availability group name must be unique on the WSFC. The maximum length for an availability group name is 128 characters. Availability replicas: Each availability group supports one primary replica and up to eight secondary replicas.