Storage Area Network (SAN) is a high-speed sub network 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.
A SAN (Storage Area Network) is a network specifically dedicated to the task of transporting data for storage and retrieval. SAN architectures are alternatives to storing data on disks directly attached to servers or storing data on Network Attached Storage (NAS) devices which are connected through general purpose networks.