Revision as of 08:50, 17 May 2009

Definition

Storage Area Network (SAN)

1. A network whose primary purpose is the transfer of data between computer systems and storage elements and among storage elements.

A SAN consists of a communication infrastructure, which provides physical connections, and a management layer, which organizes the connections, storage elements, and computer systems so that data transfer is secure and robust. The term SAN is usually (but not necessarily) identified with block I/O services rather than file access services.

2. A storage system consisting of storage elements, storage devices, computer systems, and/or appliances, plus all control software, communicating over a network.

The SNIA definition specifically does not identify the term SAN with Fibre Channel technology. When the term SAN is used in connection with Fibre Channel technology, use of a qualified phrase such as "Fibre Channel SAN" is encouraged. According to this definition, an Ethernet-based network whose primary purpose is to provide access to storage elements would be considered a SAN. SANs are sometimes also used for system interconnection in clusters.

• definition source Storage Networking Industry Association (SNIA) definition
• SNIA's] full definition of a SAN

See also

Network Attached Storage (NAS)

Differences between a SAN and a NAS

How the terms DAS NAS and SAN are used by the storage industri

A NAS is defined by SNIA as

systems that provide file services to host computers using file access protocols

A SAN is is defined by SNIA as

The term SAN is usually (but not necessarily) identified with block I/O services rather than file access services.

Conclusion

• A NAS can always be called a SAN
• A SAN can not necessarily be called a NAS unless it offers File Services via a network.

A NAS using a SAN backend

It is possible for a NAS to use a SAN backend as displayed in picture 2.

picture 2: A NAS with a SAN backend

Additional reading

• IP Storage White Paper by SNIA