Active/Active vs Active/Passive clustering Normally I talk in terms of Multi-instance or single instance 2 node clusters. I find that more people use the terms Active/Active and Active/Passive to detail what the cluster is actually doing (rather than single instance multi-instance). For what people mostly call Active/Active clusters is really a mutli-instance (in terms of SQL Server) cluster with each node owning a running instance with resources leading to both nodes Actively running business logic. In this scenario I mostly see each node owning an instance and having both nodes as possible owners so that if something should happen failover can occur. For what people mostly call Active/Passive clusters I normally find a single instance of SQL Server (although I have come across a few cases of multi-instance) that runs on one node Actively and the other node does nothing but sit and wait for a failover to occur (passive node). In the few cases I have come across there was more than