1 - Introduction

Abstract

This chapter is a good start to take computer professionals a long way in furthering the understanding of how to use the TruCluster Server product and Clustering technology in general to help its users meet the primary challenges. A cluster is a type of parallel or distributed computer system that forms, to varying degrees, a single, unified resource composed of several interconnected computers. Each interconnected computer has one or more processors, Input/Output (I/O) capabilities, an operating-system kernel, and memory. What differentiates clustering from distributed computing is that with a cluster, a number of similar computers work together and form a cadre. TruCluster Server is an amalgam of Tru64 UNIX software, storage devices, cluster interconnects, and two or more AlphaServer systems that operate together as a single virtual system. There are three basic types of UNIX clusters: the Failover Cluster, the Single System Image (SSI) Application Cluster, and the Single Systems Image (SSI) Systems Cluster. There would be four different types of UNIX clusters for Linux or Beowulf Clustering. The Failover Cluster is currently the most common form of UNIX clustering. In its many developments, it is available from most major computer hardware and system software vendors. What made the TruCluster Software version 1.0 product truly unique compared to DECsafe ASE was that it was the first UNIX-based cluster product to include support for cluster-aware applications with TruCluster Server, it is possible to create real single-systems image systems clusters from individual Tru64 UNIX servers.