AlwaysOn Overview
OVERVIEW An availability group supports a failover environment for a discrete set of user databases, known as availability databases, that fail over together. An availability group supports a set of primary databases and one to eight sets of corresponding secondary databases. Secondary databases are not backups. Continue to back up your databases and their transaction logs on a regular basis. Each set of availability database is hosted by an availability replica. Two types of availability replicas exist: a single primary 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. The primary replica makes the primary databases available for read-write connections from clients. Also, in a process known as data synchronization, which occurs at the database level. The primary replica sends transaction log records of each primary databa...