Microsoft® SQL Server 2012 Unleashed

Database Mirroring

The database mirroring feature available in SQL Server 2012 provides a solution for increasing database availability. Essentially, database mirroring maintains two copies of a single database that reside on different instances of SQL Server, typically on server instances that reside on computers in different locations. In a typical database mirroring scenario, one server instance serves as the primary database to which the client applications connect, and the other server instance acts as a hot or warm standby server.

Database mirroring involves reapplying every modification operation that occurs on the primary database onto the mirror database as quickly as possible. This is accomplished by sending every active transaction ...