In storage networking terminology, a Storage Area Network (SAN) is a high-speed subnetwork of shared storage devices. A storage  device is a machine that contains nothing but a disk or disks for storing data.

A SAN's architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. As more storage devices are added to a SAN, they too will be accessible from any server in the larger network. In this case, the server merely acts as a pathway between the end user and the stored data.

Because stored data does not reside directly on any of a network's servers, server power is utilized for business applications, and network capacity is released to the end user.