High Availability (Replication)
Replication uses a publish-subscribe model, allowing a primary server, referred to as the Publisher, to distribute data to one or more secondary servers, or Subscribers. Replication allows real-time availability and scalability across these servers. It supports filtering to provide a subset of data at Subscribers, and also allows partitioned updates. Subscribers are online and available for reporting or other functions, without query recovery. SQL Server offers three types of replication: snapshot, transactional, and merge. Transactional replication provides the lowest latency and is most commonly used for high availability. For more information, see Improving Scalability and Availability.
For information about additional high-availability solutions and how to select among them, see High Availability Solutions Overview.