Sql-server – Multi-Instance Failover Cluster SQL Cluster

clusteringsql serverwindows

Currently planning on building a new SQL Server Cluster enviroment, we currently have 2 node 2 instance Active/Active cluster.

One of the clusters has had heavy hitting security/monitoring apps and also they've put user facing toolsets on there too.

Would it be possible have a Active/Active/Active 3 node 3 Instance Cluster? So each Instance was on its own node?

We had suggested Active/Active/Passive but one of the requirements from the client was each instance is active on its own node

Best Answer

Points to note:

  • A 3 node cluster requires SQL Server Enterprise Edition. You can deploy a 2 node cluster using Standard Edition.
  • If you are placing an active instance on each node, then each node will need to be licensed. That is 4 cores per node as a minimum so at least 12 SQL Server Enterprise Edition core licenses, possibly more if your load requires it.
  • You need to thoroughly test performance with all instances running on one node. If you lose two nodes and all instances fail over to a single node, can your hardware cope with the load?
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