SQL Server Improves Replication, Availability

SQL Server 2012 provides a new infrastructure for replicating databases from server to server, called AlwaysOn. This new infrastructure could increase server availability (uptime) and speed disaster recovery (such as recovery from loss of a data center) by simplifying configuration and management and broadening the capabilities of SQL Server database mirroring technology.

High Availability and Disaster Recovery in SQL Server Today

SQL Server already has technologies to address two common requirements of any critical database, high availability and disaster recovery.

High availability is provided by a secondary source of data, which is ready should the primary source become temporarily unavailable due to server load, hardware failure, or a scheduled update. The former primary source remains generally available at some time in the future to resume the primary role or assume the secondary role. A key aspect of high availability is providing the switchover (failover) to the secondary source with as little downtime as possible. Availability measures are generally calculated as a percentage uptime per year, with the percentage of time closest to 100% being the desired goal.