Cluster deployment and operation options

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Cluster deployment and operation options

For the single quorum device and majority node set server cluster models, there are many ways of deploying and operating your server cluster to best match the needs of your organization. These modes of operation (specified by defining the failover policies of the server cluster) are outlined in the table below.

For more information on these different modes of operation and example scenarios, see the Windows Deployment Guide.

For more information on cluster models, see Choosing a Cluster Model.

Operation Mode	Description	Implementation Guide
N-node Failover Pairs	In this mode of operation, each application is set to fail over only between 2 specified nodes.	Limit the possible owner list for each resource group to a given pair of nodes. For more information, see Specify which nodes can own a resource.
Hot-Standby Server /N+I	Hot-standby server operation mode reduces the overhead of failover pairs by consolidating the "spare" node for each pair into a single node, providing a hot-standby server that is capable of running the applications from each node pair in the event of a failure. This mode of operation is also referred to as active/passive. For larger clusters, N+I mode provides an extension of the hot-standby server mode where N cluster nodes host applications and I cluster nodes are spare nodes.	Use a combination of the preferred owners list and the possible owners list. Set the preferred node to the node that the application will run on by default and set the possible owners for a given resource group to the preferred node and the spare node. For more information, see Specify preferred owners of a group and Specify which nodes can own a resource. For N+I configurations, see article Q296799, "How to Configure Windows Clustering Groups for Hot Spare Support" in the Microsoft Knowledge Base.
Failover Ring	In this mode of operation, each node in the cluster runs an application instance. In the event of a failure, the application on the failed node is moved to the next node in sequence.	Define the order of failover for a given resource group using the preferred owner list. Choose a node order, with the preferred node list for each group starting at a different node. For more information, see Specify preferred owners of a group.
Random	For large clusters running multiple applications, the best policy in some cases is to allow the server cluster to choose the fail over node at random.	Do not define a preferred owners list for the resource groups. Each resource group that has an empty preferred owners list will be failed over to a random node in the cluster in the event that the node currently hosting that group fails.