# Sql-server – Failover Cluster and AlwaysOn Availability Groups across Data Centers

availability-groupsclusteringhigh-availabilitysql serversql-server-2012

We have two 3 node clusters in separate data centers, let's call them ClusterP and ClusterS.

ClusterP is our primary and ClusterS is our secondary for disaster recovery. Each cluster has multiple failover cluster instances on it but they are completely segregated from each other.

We'd like to introduce AlwaysOn Availability Groups from ClusterP to ClusterS. I've read multiple guides to this and there is one question I can't really answer. We do NOT have the ability to have cross-datacenter shared storage (no SAN mirroring across datacenters). With this setup, is it possible to setup AlwaysOn Availability Groups?

I understand if we had a standalone server in the secondary datacenter, we could setup an AG with an FCI by adding that server as a node in WFCS, removing it as an owner from any of the FCIs on ClusterP, and setting it up as an AG member. This method does not use shared storage based on my research.

My confusion comes from having two-three node clusters and how they can work together with AGs. It seems to me I need to disband the cluster on ClusterS, add the nodes to ClusterP, add the FCIs needed then setup the nodes so that the physical nodes in location of ClusterS can only host those FCIs and the nodes in location of ClusterP can only host those FCIs. Will this work?

I'd appreciate any tips.