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.
A SAN moves storage resources off the common user network and reorganizes them into an independent, high-performance network. This allows each server to access shared storage as if it were a drive directly attached to the server. When a host wants to access a storage device on the SAN, it sends out a block-based access request for the storage device.
The main benefit to using a SAN is that raw storage is treated as a pool of resources that can be centrally managed and allocated on an as-needed basis. SANs are also highly scalable because additional capacity can be added as required.
The main disadvantages to SANs are cost and complexity. SAN hardware tends to be expensive, and building and managing a SAN requires a specialized skill set. Read more