Refers to multiple service groups running on multiple servers, with each service group capable of being failed over to different servers in the same cluster, and also to different servers in a linked cluster. For example, consider a four-node cluster with each node supporting three critical database instances and a linked two-node back-up cluster. If all nodes in the four-node cluster fail, each instance is started on a node in the linked back-up cluster. Also called Any-to-Any.