Microsoft SQL Server 2012 Bible

Summary

Database mirroring is an inexpensive software-based solution to achieve high database availability. Database mirroring works by transferring transaction log records from the production database on one SQL Server to a mirror database on another SQL Server over the network, either synchronously or asynchronously. Asynchronous database mirroring provides the best performance but has potential for data loss and does not support automatic failover. Synchronous database mirroring provides a higher level of data protection than asynchronous mode and provides automatic and manual failover options at the cost of reduced application performance.

AlwaysOn Availability Groups is a robust high-availability solution that offers a scalable and flexible architecture for your databases. Availability groups work much like mirroring; however, you can transfer and failover one or more databases together in a group. Through the use of Windows Failover Cluster Service (WSFC), AlwaysOn Availability Groups can maintain high availability and scalability across your network.

At first glance, database mirroring or AlwaysOn Availability Groups may appear to be better than log shipping, but it is not a replacement for log shipping. Each solution has unique features, and depending on your business requirements, you may require selecting one or both the solutions. For example, log shipping supports multiple copies of the production databases, but database mirroring allows only one copy of the production ...