Windows NT Clusters for Availability and Scalabilty

We describe the architecture of the clustering extensions to the Windows NT operating system. Windows NT clusters provide three principal user visible advantages: improved availability by continuing to provide a service even during hardware or software failure. Increased scalability by allowing new components to be added as system load increases. Lastly, clusters simplify the management of groups of systems and their applications by allowing the administrator to manage the entire group as a single system. In this paper we first describe the high level goals for the design team, and some of the difficulties making the appropriate changes to Windows NT. We then provide an overview of the structure of the cluster specific components and discuss each component in more detail before closing with a discussion of some possible future enhancements. Overview Clusters of computer systems have been built and used for over a decade [1]. Pfister [2] defines a cluster as "a parallel or distribute..