A Storage Area Network (SAN) is an architecture attaching remote computer storage devices (such as disk arrays, tape libraries and optical disc "jukeboxes") to servers in such a way that, to the operating system, the devices appear as locally attached. Although cost and complexity are dropping, as of 2007, SANs are still uncommon outside larger enterprises.

SANs often utilize a Fibre Channel fabric topology - an infrastructure specially designed to handle storage communications. It provides faster and more reliable access than higher-level protocols used in NAS. A fabric is similar in concept to a network segment in a local area network. A typical Fibre Channel SAN fabric is made up of a number of Fibre Channel switches.

Today, all major SAN equipment vendors also offer some form of Fibre Channel routing solution, and these bring substantial scalability benefits to the SAN architecture by allowing data to cross between different fabrics without merging them. These offerings use proprietary protocol elements, and the top-level architectures being promoted are very different.

Benefits include the ability to allow servers to boot from the SAN itself. This allows for quick and easy replacement of faulty servers, since the SAN can be reconfigured so that a replacement server can use the LUN (Logical Unit Number) of the faulty server. This process can take as little as half an hour and is a relatively new idea being pioneered in data centers. There are a number of emerging products designed to help facilitate as well as further speed up this process. For example, Brocade offers an Application Resource Manager product which automatically provisions servers to boot from a SAN, with typical-case load times measured in minutes. While this area of technology is still new, many view it as being the future of the enterprise datacenter.