NAS and SAN may only contain the same letters but they are in fact completely different types of storage systems. SAN is a storage area network, while NAS is a network attached storage. Both usually use some type of RAID and are connected to a network, but the difference between SAN and NAS is that, a NAS is a storage device which operates on data files, whereas SAN is a local network of multiple devices which operate on disk blocks.
Most of the computer systems can be connected to the Local Area Network (LAN) would use CIFS, Samba, AFP, protocols to get connected to a NAS for retrieval of data. In order to connect to a SAN, a SCSI Fibre Channel infrastructure is required that may consist of Fibre Channel Switch, and a Fibre Channel Card on the client side.
An administrator of a home or small business network is capable of connecting a NAS device to their Local Area Network. The NAS retains its own IP address comparable to computer and other TCP/IP devices. By installing additional NAS devices to the network, you can increase the storage capacity. Every NAS retains its independent characteristics of operability.
If you are managing a bigger network and may need a lot of space and fast transfer rates for your centralized storage, you may want to opt for an installation of a single SAN, which may offer the expected scalability and higher performance. one important thing to remember when deciding on the SAN or NAS environment, is that SAN is a much more expensive technology that requires each client to have a Fibre Channel Cards as well as a centralized Fibre Channel Switch.
The SAN’s storage usually consists of several large arrays of high-speed SAS disks spinning from 10 to 15K rpm, although now some companies starting to use solid-state disks in some cases where performance and energy saving are priorities and money is no object. Typically, SAN is used for mission-critical environment, such as databases, Video Editing, and graphics design, where reliability and performance are key.
As Internet technologies like TCP/IP and Ethernet have advanced over the years, so has the NAS technology. Some SAN products are making the transition from Fibre Channel to the same IP-based approach as NAS uses. With the rapid improvements in disk storage technology, today’s NAS devices now offer capacities and performance that were once only attainable by SAN. These two industry factors have led to a partial convergence of NAS and SAN approaches to network storage.
Many companies like NetApp, EMC, Isilon, Omenon MeidaGrid offer various types and combinations of high availability, high bandwidth NAS/SAS environments, that many corporations and broadcast television stations use on the daily bases. Again each one has its pros and cons, but I will not go in to the specifics at this point.