Beowulf Cluster

A Beowulf cluster is a high-performance computing (HPC) cluster assembled from commodity, off-the-shelf computers and open source software, all connected over a fast network so they can pool their processing power on a single task. Instead of one purpose-built supercomputer, a Beowulf design wires together many ordinary servers as compute nodes and coordinates them with software such as Linux and a message-passing library. The approach made HPC affordable and accessible far beyond the organizations that could buy specialized hardware.

What a Beowulf cluster is

The Beowulf architecture emerged in the mid-1990s. Before then, parallel computing and HPC usually required entirely specialized, dedicated computer architectures. As networks grew faster and the MPI standard took shape, building those custom machines fell out of favor. It became cheaper and simpler to network together large numbers of commodity-grade computers, standard rack-mount servers, tower desktops, and at times even gaming consoles, and let them share the load.

The defining traits are consistent:

• Commodity hardware rather than custom or proprietary machines.
• Open source software such as Linux or FreeBSD to manage and distribute work.
• A high-speed network connecting the nodes for fast data exchange.
• Parallel processing, splitting a workload across nodes so many processors work at once.

Why Beowulf clusters matter

Most modern supercomputers now follow the Beowulf model: multiple standard server-class computers networked over an extremely fast interconnect, with fast shared storage attached. This design won because it is cost-effective, flexible, and easy to grow. It brought serious computing power to scientific research, financial modeling, weather forecasting, engineering simulation, and more, using hardware any organization can buy.

Fault tolerance is another advantage. Because the cluster is built from many independent nodes, the loss of one node does not necessarily halt the whole system.

How Beowulf clusters scale

A Beowulf cluster grows in two directions, and the commodity design makes both straightforward:

	Scaling out	Scaling up
Method	Add more compute-node servers of the same type	Upgrade existing nodes
Example	Buy additional identical servers	Add CPUs, RAM, or GPUs to current servers
Effect	More nodes working in parallel	More power per node

Because every node is a standard machine, scaling out is often as simple as buying more of the same servers you already run and adding them to the cluster.

Software for Beowulf clusters

Several open source stacks are built to manage Beowulf-style systems. General-purpose operating systems like Linux and FreeBSD provide the foundation, with strong support for high-performance networking such as InfiniBand and high-speed Ethernet. Dedicated cluster toolkits, historically Rocks Cluster, Scyld ClusterWare, and xCAT (Extreme Cluster Administration Toolkit), add provisioning, job scheduling, monitoring, and management so administrators can operate many nodes as one coherent system.