Answer:
A storage area network (SAN) is a dedicated high-speed network or subnetwork that interconnects and presents shared pools of storage devices to multiple servers.
The availability and accessibility of storage are critical concerns for enterprise computing. Traditional direct-attached disk deployments within individual servers can be a simple and inexpensive option for many enterprise applications, but the disks -- and the vital data those disks contain -- are tied to the physical server across a dedicated interface, such as SAS. Modern enterprise computing often demands a much higher level of organization, flexibility and control. These needs drove the evolution of the storage area network (SAN).
SAN technology addresses advanced enterprise storage demands by providing a separate, dedicated, highly scalable high-performance network designed to interconnect a multitude of servers to an array of storage devices. The storage can then be organized and managed as cohesive pools or tiers. A SAN enables an organization to treat storage as a single collective resource that can also be centrally replicated and protected, while additional technologies, such as data deduplication and RAID, can optimize storage capacity and vastly improve storage resilience -- compared to traditional direct-attached storage (DAS).
SAN architecture
A storage area network consists of a fabric layer, host layer and storage layer.
