Server Cluster Resources
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Server cluster resources
A cluster resource is any physical or logical component that has the following characteristics:
Can be brought online and taken offline.
Can be managed in a server cluster.
Can be hosted (owned) by only one node at a time.
To manage resources, the Cluster service communicates to a resource dynamic-link library (DLL) through a Resource Monitor. When the Cluster service makes a request of a resource, the Resource Monitor calls the appropriate entry-point function in the resource DLL to check and control the resource's state. For more information on Resource Monitor or resource DLL, see Resource Monitors or Resource dynamic-link libraries (DLLs) in clusters running Windows Server 2003.
Dependent resources
A dependent resource is one that requires another resource to operate. For example, a network name must be associated with an IP address. Because of this requirement, a Network Name resource is dependent on an IP Address resource. Dependent resources are taken offline before the resources upon which they depend are taken offline, likewise, they are brought online after the resources on which they depend are brought online. A resource can specify one or more resources on which it is dependent. Resource dependencies also determine bindings. For example, clients will be bound to the particular IP address that a Network Name resource is dependent on.
When creating resource dependencies, take into account the following: some dependencies are strictly required, while others are not required but make sense to do so. For example, a file share that is not a DFS root has no required dependencies, but if the Disk resource that holds the file share fails, the file share will be inaccessible to users. Therefore, it is logical to make the file share dependent on the Disk resource.
A resource can also specify a list of nodes on which it is able to run. Possible nodes and dependencies are important considerations when administrators organize resources into groups. For more information on preferred nodes and groups, see Server Cluster groups. For more information on nodes, see Nodes.
The following topics describe important concepts related to resources: