Hello All, I'm a bit confused with some of the terms used in an active/active cluster configuration. In setting up an active/active cluster. The one terminnolgy that is confusing me is the word "instance". I'm trying to setup a 2 node active/active cluster. Both nodes will be connected to a shared SAN storage unit. I undertand each node must have its own disk group plus the quorum disk. So 3 disk groups. But I how many sql server instances need to be installed per node. I want to have 2 virtual sql servers. Please correct me if I wrong. My understading for an active/active setup is you will need 2 sql server installations per node, 1 default instance and a 2nd named instance. So I will have node A and B with both haveing 2 sql server instance each. 4 instance of SQL on the cluster with 2 virtual sql servers. The named instances will be passive on both nodes and the default instance are active. If node B fails, the default instance of node B will fail over to the named instance of node A and if node A failes, it will fail over to the named instance of node B. The term "instance" is it used to describe the virtual servers or the actual sql server installations in each node? Please help I'm very confused, also if someone knows a good source of infomation on setting up active/active cluster that will be great help. Thanks all.