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Microsoft Cluster Server (MSCS) for Windows NT Server, Enterprise Edition(NTS/E) provides higher availability and easier manageability for importantresources and applications. MSCS runs as a system service and monitors thehealth of resources defined within the cluster. Cluster resources areorganized by groups of similar or dependent resources.
Using MSCS, groups of resources may be defined to develop logical groupingsfor important resources. Some examples of resource types may beapplications, services, disks, file shares, print spoolers, TCP/IPaddresses, network names, and so on. Other types of resources within thecluster may be added by software developers through custom DLLs ifnecessary. Many applications and services may not require special handlingand may use generic resource types as provided with the product.
Groups of resources allow similar or dependent resources to be groupedtogether. For clients to access resources within a group, the group musthave a network name and IP address resource associated with it.
These groups of resources may be owned and managed by any member computer(node) in the cluster. In the event of a failure within a group, thecluster software transfers the group of resources and data to a remainingnode in the cluster. The network name, address, and other resources for themoved group remain with the group after the transfer. Therefore, clients onthe network may still access the same resources by the same network nameand IP address -- despite the name of the computer that offers theresources. Thus, these resources become more available. Groups may be movedautomatically because of a resource failure within the group, or by anadministrator for load balancing or administrative purposes.
Multiple groups may be created within the cluster so that resources may bedistributed among available nodes in the cluster. The ability to distributegroups independently allows the workload to be handled by more than onecluster node. Administrators may use each cluster node for normal day today operations. In the event of a failure, the groups handled by a failingnode will be automatically transferred to surviving nodes within thecluster.
Resource dependencies may be established within a group to ensureavailability of specific resources before other resources attempt to goonline. For example, a file share resource may require a physical disk tobe online to provide data to clients.
Another example of resource dependencies may be for a Web server resourcethat needs an IP address to start. If you create the resource with adependency on the IP address resource, the web service will not attempt tostart until this becomes available.
For more information on groups and resources within MSCS, consult the MSCSAdministrator's Guide. The Administrator's Guide is located on CD-ROM 1 in the Support/Books folder, in addition to the hard copy that is received with the Enterprise product.