Differences Between NAS, SAN, and DAS

There are three commonly used methods for storing data that nearly all storage technologies fall into: Network Attached Storage, Direct-Attached Storage, and Storage Area Network. When deciding what configuration is best for you, it’s important to know a little bit about them, how they are similar and how they are different.

Direct-attached storage, or DAS, is a computer storage technology that is connected directly to the host computer or server. The popularity of DAS can be attributed to its ease of use and low cost compared to networked storage. DAS is the simplest level of storage, and is different from storage area networks (SAN) and network attached storage (NAS) in that it is not connected to, or accessible directly by, the network.

Network Attached Storage, or NAS, is a computer storage technology that connects to a computer or server via a network as a single device. It utilizes Ethernet and TCP/IP connections and in this way operates as a file server. NAS is limited exclusively to file sharing, and does not provide any other functions. NAS is different from another common form of storage, Direct Attached Storage (DAS), in that it is not connected directly to the accessing computer system and is instead accessed via the network. A NAS device offloads storage functions from the server, providing data to the accessing user.  The advantages of NAS over other storage methods include faster access to information and its accessibility from anywhere in the network.

Storage Area Network, or SAN, is a computer storage technology that is comprised of multiple storage devices networked together. SAN differs from network attached storage (NAS) in that where NAS in a single storage device, a SAN is comprised of multiple storage devices networked together, commonly through high performance Fiber Channel interconnects. A SAN is advantageous in enterprise level networks with large storage needs where high-performance is required. A single SAN is more practical than, and can take the place of, multiple NAS devices all while providing greater storage space and higher performance.