Clustering

One of the most common uses of clustering is to balance the load of a high-traffic website. In this scenario, the request for a web page is forwarded to a manager server. The manager server specifies which of several similar or identical servers to forward the request to. This formation is often referred to as a web farm, a configuration that allows traffic to be managed faster with more efficiency. Clustering has been around since the 1980s, first used in VMS systems by DEC. Sysplex is a similar approach used for IBM mainframe systems. Microsoft, Sun Microsystems and other leading companies also provide clustering packages that offer both availability and scalability. As traffic and assurance of availability increases, all or certain sections of a cluster can be increased in either size or number. Clustering is also used as a more affordable variation of parallel processing for applications that contribute to parallel operations. An example of this is the Beowulf project in which a group of off-the-shelf computers were used to create a cluster for scientific applications.