Implementing DR with AlwaysOn Availability Groups
In Chapter 5, we successfully implemented high availability for the App1Customers and App1Sales databases through the App1 availability group. In this chapter, we will discuss how we can also implement disaster recovery for these databases. To do this, we first need to build out a new server in our second site and install a stand-alone instance of SQL Server. Because the cluster now spans two sites, we need to reconfigure it as a multi-subnet cluster. We also need to reconfigure the quorum model to remove its dependency on the shared storage, which we currently have for the quorum. Once this is complete, we are able to add the instance on the new node to our availability group. The following sections assume that you have already built out a third server with a SQL Server instance called CLUSTERNODE3\ASYNCDR, and they demonstrate how to reconfigure the cluster as well as the availability group.