Resource Monitors

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

Resource Monitors

A Resource Monitor is a cluster component that acts as an intermediary between the Cluster service and a resource dynamic-link library (DLL). When the Cluster service makes a request of a resource, the Resource Monitor transfers that request to the appropriate resource DLL. When a resource DLL must report status or notify the Cluster service of an event, the Resource Monitor ensures that the information is delivered successfully. Resource Monitors are passive communication layers; they do not initiate operations.

The Resource Monitor runs in a process separate from the Cluster service for the following reasons:

• To protect the Cluster service from resource failures.

• To allow the Resource Monitor to take action if the Cluster service fails. The Resource Monitor detects Cluster service failure and responds by taking all of the resources and groups on the affected node offline.

Every cluster node runs one or more Resource Monitors. By default, the Cluster service starts only one Resource Monitor to interact with all of the resources hosted by the node. However, this default can be overridden by an administrator using either Cluster Administrator or another management application. Assign potentially problematic resource DLLs to their own Resource Monitor to prevent faulty behavior from affecting other resources and other Resource Monitors.

• For more information on the Cluster service, see Cluster service.

• For more information on Cluster Administrator, see Cluster Administrator.

• For more information on the resource DLLs, see Resource dynamic-link libraries (DLLs) in clusters running Windows Server 2003.