Cluster Basics

What is a Cluster?

An HPC cluster is a set of computers gathered together and connected with the intent of merging their processing power towards the same goal. There are several types of clusters, but the most common is the so-called "Beowulf" cluster, which is normally made out of commodity hardware and networking facilities. This is the kind of cluster we target to build with Moab Cluster Builder.

How Does a Cluster Work?

The underlying concept in HPC is interprocess communication. This allows many processors to work on the same task in parallell by splitting the workload and communicating with each other to gather the processed data. The most common kind of interprocess communication over networked clusters is Message Passing Interface (MPI), a standard upon which many libraries are built.

On top of intercommunicating processes there has to be management software that allows the control of process groups (jobs) and a scheduler that implements decisions and policies on the job queues.