Does the Windows Failover Cluster for a multi-subnet SQL Server Availability Group require a static IP entry for each subnet?
The instructions I am finding for a Failover Cluster Instance (FCI) in a multi-subnet environment require separate IPs but I am not creating any FCIs – only an availability group.
I am running SQL Server 2012 on Windows Server 2012 Hyper V VMs in 2 separate subnets in the same domain. I understand that I will need an IP from each subnet when I create the listener for my AAG. What I am unclear on is the configuration of IPs on the underlying Windows Failover Cluster.
Can I get away with using a single IP in the same subnet as the primary replica or do I need to add an IP from the secondary replica's subnet as well?
Also, if the server hosting the secondary replica does require its own IP, does it also require its own unique cluster name as stated in this blog post (and can you explain why this is necessary)?:
What you need for a Multi Subnet Configuration for AlwaysOn FCI in SQL Server 2012
Best Answer
The CNO will require an IP address for every subnet it could reside in.
For the underlying WSFC you'll need at a minimum:
Node1 - IP Address for each unique subnet for each network interface
Node2 - IP Address for each unique subnet for each network interface
CNO - IP Address for each unique subnet
EX: 2 nodes, 2 subnets, 1 interface per node, subnets 192.168.1.1/24 and 192.168.2.1/24
Node1: 192.168.1.10
Node2: 192.168.2.10
CNO: 192.168.1.20, 192.168.2.20
I'm not sure I understand this part of the question. All of the resources can only belong to a single cluster - there is no cluster inside of a cluster thing.
Edit - I looked at the link that you posted and I'm not sure why the author stated "•Cluster name for each node". My only guess is they meant each node needs a name and IP (for the node). Otherwise it's not a correct statement, the author should probably be contacted.