SAN Vs. NAS

SAN (storage area network) is is a dedicated network that provides access to block level storage. SANs are used to make storage devices, such as disk array and are accessible to servers so that they look as if there are locally attached to an operating system.

Data in SAN (Storage Area Network) can be stored using two basic modules as DAS (Direct Attached Storage) and NAS (Network Attached Storage). A network, which is created by attaching storage devices such as disk arrays and tapes to a common server so that the storage devices appear to be confined to operating system, is known as storage area network. DAS is named because it is a directly attached to a server without any intermediary network involved. Main distinguishing character of DAS (Direct Attached Storage) is its direct connectivity through a host bus adapter without the use of the networking devices as hubs, bridges and switches. In a network attached storage system, many independent clients can access the storage memory. The aim of the NAS (Network Attached Storage) is to provide only file based storage devices.  In the same way we can convert NAS (Network Attached Storage) to a DAS (Direct Attached Storage) by disconnecting the entire network and attach the port to a single computer.