Network-attached storage
NAS Recovery - Network-attached storage
Network-attached storage (NAS) is a computer data storage that provides data access to heterogeneous clients connected to the network. NAS does not perform general computing tasks. However, it may be possible to run other software on it. A NAS unit is usually controlled and configured over the network by connecting a browser to the network address.
NAS consists of one or more hard disks arranged in the form of redundant array of independent disks (RAID). NAS provides both storage and filesystem. This feature of NAS differentiates it from the similar storage technique, storage area network (SAN), which provides only block-based storage and leaves filesystem issues for the client. NAS uses file-based protocols such as NFS, SMB/CIFS and AFP.
Since NAS does not perform computing tasks, it does not require a general purpose operating system. Rather, it uses a stripped down operating system with all functionality not related to data storage is stripped out. An example of such software is FreeNAS.
NAS provides several advantages. Availability of data can be increased with built-in RAID and clustering features implemented on NAS. Also, it contributes for higher performance of the system by relieving the server from the task of file serving and allowing it to perform other processing tasks in a smooth manner.
One of the drawbacks of NAS is that it is limited to its own hardware and hence not upgradeable in most cases.
NAS finds several applications in the consumer market, especially in multi-media storage applications. It gains popularity because it enables simple and low-cost systems such as load-balancing and fault-tolerant email and Web server systems by providing storage services.
