Information you need to know before setting up GeoClustering at SQL Server 2008 or SQL Server 2012
Happy New Year to everyone! :)
This week I will provide distilled information about GeoClustering.
SQL Server Failover Clustering, which includes support for both local and multisite failover configurations, is 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 one cardinal consideration to keep in mind with deploying all of these workloads on multi-site clustering is data replication. As opposed to local clusters, multi-site failover clusters share no central storage. Cluster data must be replicated and synchronized between all of the sites of a multi-site cluster. You will therefore need a third-party data replication solution. However, Windows Server 2008 takes care of the rest of the clustering needs (heartbeat monitoring, failover, etc.) in these deployment scenarios. Microsoft cannot provide or suggest methods to replicate the data between the remote sites.
Windows Failover Clustering is a prerequisite for implementing SQL Server Availability Groups, so the first reference should be these articles and whitepapers about Windows GeoCluster:
Requirements and Recommendations for a Multi-Site Failover Cluster
Microsoft Windows Multi-Site Failover Cluster Best Practices
Regarding SQLServer running on a GeoCluster:
- Availability Groups don’t exist in SQL Server 2005, 2008 or 2008 R2, so SQL Server 2012 is needed to implement them: AlwaysOn Availability Groups (SQL Server)
- SQL Server 2008 is supported running on a GeoCluster as a normal Failover Instance (as it does not have an AlwaysOn feature).
- This Whitepaper provides the information how to implement AlwaysOn at a Multi-site architecture: SQL Server 2012 AlwaysOn: Multisite Failover Cluster Instance
- If the nodes will be at different subnets, also consider this information: SQL Server Multi-Subnet Clustering (SQL Server)