SQL Server 2012 AlwaysOn: Multisite Failover Cluster Instance
Writers: Mike Weiner, Sanjay Mishra, Min He
Contributors: Lingwei Li, Mike Anderson (EMC Corporation)
Technical Reviewers: Shaun Tinline-Jones, Steve Howard, Prem Mehra, Paul Burpo, Mike Ruthruff, Jimmy May, Matt Neerincx, Dan Benediktson, Michael Steineke (Edgenet Inc.), David P. Smith (ServiceU Corporation)
Applies to: SQL Server 2012
Summary: SQL Server Failover Clustering, which includes support for both local and multisite failover configurations, is part of the SQL Server 2012 AlwaysOn implementation suite, designed to provide high availability and disaster recovery for SQL Server. The multisite failover clustering technology has been enhanced significantly in SQL Server 2012. The multisite failover cluster architecture, enhancements in SQL Server 2012 to the technology, and some best practices to help with deployment of the technology are the primary focus of this paper.
You can download the complete document here: https://download.microsoft.com/download/D/2/0/D20E1C5F-72EA-4505-9F26-FEF9550EFD44/SQLServer2012_MultisiteFailoverCluster%20(2).docx