What Is a Computer Cluster?
A computer cluster is a group of connected computers that work together as if they were one computer. Each machine connects through a fast local area network. Clusters are generally used to improve the performance or availability of a computer.
Cluster systems can be divided into four types:
- High-availability (HA) clusters, also known as failover clusters. Their main purpose is to improve service availability when a server fails. HA generally requires at least two servers and uses redundant cluster components to reduce failures caused by a single server.
- Load-balancing clusters connect a group of computers to share computation as one virtual computer. From the user’s perspective, several computers work as a single virtual machine. User requests are handled and distributed to computers in the cluster, balancing the workload across all machines and increasing processing capacity.
- Computer clusters are generally used for computation, such as weather simulations or vehicle crash simulations. They typically use dedicated machines and networks. Most are based on the Beowulf Cluster, with middleware for cluster programming such as MPI (Message Passing Interface) or PVM (Parallel Virtual Machine).
- Grid computing brings together the processing power of computer systems distributed across the internet so they work as if they were one system. A grid can also be described as presenting users with a Virtual Organization.
