Reference Guide

42 Understanding Your Failover Cluster

Quorum Resource

Normally, the quorum resource is a common cluster resource that is accessible

by all of the nodes. The quorum resource—typically a physical disk on a

shared storage system—maintains data integrity, cluster unity, and cluster

operations.

When the cluster is formed or when the nodes fail to communicate, the

quorum resource guarantees that only one set of active communicating nodes

is allowed to form a cluster. If a node fails and the node containing the

quorum resource is unable to communicate with the remaining nodes, MSCS

shuts down the node that does not control the quorum resource. If a node

fails, the configuration database helps the cluster recover a failed resource or

recreates the cluster in its current configuration.

The shared physical disk is the only resource supported by the solution that

can act as a quorum resource.

NOTE: The Majority Node Set Quorum resource type is not supported.

Additionally, the quorum resource ensures cluster integrity. MSCS uses the

quorum resource’s recovery logs to update the private copy of the cluster

database in each node, thereby maintaining the correct version of the cluster

database and ensuring that the cluster is intact.

The operating system uses the quorum resource to ensure that only one set of

active, communicating nodes is allowed to operate as a cluster. A node can

form a cluster only if the node can gain control of the quorum resource.

A node can join a cluster or remain in an existing cluster only if it can

communicate with the node that controls the quorum resource.

Resource Failure

MSCS periodically launches the Resource Monitor to check if a resource is

functioning properly. Configure the Looks Alive and Is Alive polls to check

for failed resources. The Is Alive poll interval is typically longer than the

Looks Alive poll interval because MSCS requests a more thorough check of

the resource's state.

NOTE: Do not adjust the Looks Alive and Is Alive settings unless instructed to do so

by technical support.