As part of any enterprise application implementation, a systems designer must provide the applications and services in a way that is fault-tolerant and reliable. As computing has moved from mainframe-based systems to client/server systems, applications have suffered large blows to performance and reliability. The introduction of the cluster server seeks to change that. Already, cluster server software vendors are providing low-cost software options that allow systems engineers to rival mainframe reliability with client/server architectures.
As you will see, clustered and load balanced solutions meet the needs of fault tolerance by providing failover for systems and services that are critical to the enterprise. They meet the needs of performance and scalability by providing a system that can grow as needed, without having to replace hardware. They meet the needs of reliability and availability by providing a platform that can be upgraded, modified, and maintained without an interruption of service.