HP Integrity Superdome SX2000 Cluster Installation and Configuration Guide - W - Page 12

You will not need an advanced degree to get failover clusters working. The main reason for this change is that the new administrative interface does the heavy lifting for you. In previous versions of failover clustering, you had to learn an unintuitive, cluster-centric vocabulary and then try to figure out what those words really meant. There is no need to learn the intricacies of cluster vocabulary with Windows Server 2008 failover clustering. Instead, configuration is task based. You are asked if you want to create a highly available file server, Dynamic Host Configuration Protocol (DHCP) server, Windows Internet Name Service (WINS) server, or other type of server and then the wizard walks you through the process. Cluster Terminology A working knowledge of clustering begins with the definition of some common terms. The following terms are used throughout this document. Nodes Individual servers or members of a cluster are referred to as nodes or systems (the terms are used interchangeably). A node can be an active or inactive member of a cluster, depending on whether or not it is currently online and in communication with the other cluster nodes. An active node can act as host to one or more cluster groups. Cluster Service Cluster service refers to the collection of clustering software on each node that manages all cluster-specific activity. Shared Disks Shared disks are devices (normally hard disk drives) that the cluster nodes are attached to by a shared bus. Applications, file shares, and other resources to be managed by the cluster are stored on the shared disks. Resources Resources are physical or logical entities (such as file shares) managed by the cluster software. Resources can provide a service to clients or be an integral part of the cluster. Examples of resources are physical hardware devices such as disk drives, or logical items such as IP addresses, network names, applications, and services. Resources are the basic unit of management by the cluster service. A resource can only run on a single node in a cluster at a time, and is online on a node when it is providing its service on that node. At any given time, a resource can exhibit only one of the following states: • Offline • Offline pending • Online • Online pending • Failed When a resource is offline, it is unavailable for use by a client or another resource. When a resource is online, it is available for use. The initial state of any resource is offline. When a resource is in one of the pending states, it is in the process of either being brought online or taken offline. If the resource cannot be brought online or taken offline after a specified amount of time, and the resource is set to the failed state, you can specify the amount of time that cluster service waits before failing the resource by setting its pending timeout value in Failover Cluster Management tool. Resource state changes can occur either manually (when you use the Failover Cluster Management tool to make a state transition) or automatically (during the failover process). When a service 12 Introduction