Introduction (Guide to Creating and Configuring a Server Cluster under Windows Server 2003 White Paper)

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Applies To: Windows Server 2003 with SP1

A server cluster is a group of independent servers working collectively and running the Microsoft Cluster service (MSCS). Server clusters provide high availability, failback, scalability, and manageability for resources and applications

Server clusters allow client access to applications and resources in the event of failures and planned outages. If one of the servers in the cluster is unavailable because of a failure or maintenance requirements, resources and applications move to other available cluster nodes.

For Windows Clustering solutions, the term “high availability” is used rather than “fault tolerant.” Fault-tolerant technology offers a higher level of resilience and recovery. Fault-tolerant servers typically use a high degree of hardware redundancy plus specialized software to provide near-instantaneous recovery from any single hardware or software fault. These solutions cost significantly more than a Windows Clustering solution because organizations must pay for redundant hardware that waits in an idle state for a fault.

Server clusters do not guarantee non-stop operation, but they do provide sufficient availability for most mission-critical applications. The cluster service can monitor applications and resources and automatically recognize and recover from many failure conditions. This provides flexibility in managing the workload within a cluster. It also improves overall system availability.

Cluster service benefits include:

  • High Availability: With server clusters, ownership of resources such as disk drives and Internet protocol (IP) addresses is automatically transferred from a failed server to a surviving server. When a system or application in the cluster fails, the cluster software restarts the failed application on a surviving server, or disperses the work from the failed node to the remaining nodes. As a result, users experience only a momentary pause in service.

  • Failback: The Cluster service will automatically re-assign the workload in a cluster when a failed server comes back online to its predetermined preferred owner. This feature can be configured, but is disabled by default.

  • Manageability: You can use the Cluster Administrator tool (CluAdmin.exe) to manage a cluster as a single system and to manage applications as if they were running on a single server. You can move applications to different servers within the cluster. Cluster Administrator can be used to manually balance server workloads and to free servers for planned maintenance. You can also monitor the status of the cluster, all nodes, and resources from anywhere on the network.

  • Scalability: Cluster services can grow to meet increased demand. When the overall load for a cluster-aware application exceeds the cluster’s capabilities, additional nodes can be added.

This document provides instructions for creating and configuring a server cluster with servers connected to a shared cluster storage device and running Windows Server 2003 Enterprise Edition or Windows Server 2003 Datacenter Edition. Intended to guide you through the process of installing a typical cluster, this document does not explain how to install clustered applications. Windows Clustering solutions that implement non-traditional quorum models, such as Majority Node Set (MNS) clusters and geographically dispersed clusters, also are not discussed. For additional information about server cluster concepts as well as installation and configuration procedures, see the Windows Server 2003 Online Help.