A network-attached storage (NAS) device is a
server that is dedicated to nothing more than file sharing. NAS does not provide any of the activities that a server in a server-centric system typically provides, such as
e-mail,
authentication or file management. NAS allows more
hard disk storage space to be added to a
network that already utilizes servers without shutting them down for maintenance and upgrades. With a NAS device, storage is not an integral part of the server. Instead, in this storage-centric design, the server still handles all of the processing of data but a NAS device delivers the data to the user. A NAS device does not need to be located within the server but can exist anywhere in a
LAN and can be made up of multiple networked NAS devices.