A storage area network (SAN) or storage network is a Computer network which provides access to consolidated, block level data storage. SANs are primarily used to enhance storage devices, such as disk arrays and tape libraries, accessible to servers so that the devices appear to the operating system as locally attached devices. A SAN typically is a separate network of storage devices not accessible through the local area network (LAN) by other devices.
The cost and complexity of SANs dropped in the early 2000s to levels allowing wider adoption across both enterprise and small to medium-sized business environments.
A SAN does not provide file abstraction, only block-level operations. However, file systems built on top of SANs do provide file-level access, and are known as shared-disk file systems.