Network-attached storage (NAS) is file-level computer data storage connected to a computer network providing data access to a group of clients. NAS not only operates as a file server, but is specialized for this task either by its hardware, software, or configuration of those elements. NAS is often manufactured as a specialized computer built for storing and serving file, rather than simply a general purpose computer being used for the role. They do not have a keyboard or display, and are controlled and configured over the network, often using a browser.
NAS systems contain one or more hard drives, often arranged into logical, redundant storage containers or RAID. Network attached storage removes the responsibility of file serving from other servers on the network. They typically provide access to files using network file sharing protocols.
The speed is usually a 1GB Ethernet connection, but it can be changed to a multiple gigabit connection or a fiber optic connection by adding a PCIe network card. It depends on the NAS device. The capacity range varies. They can be built up to 40TB devices, but typical you will see 2 or 4TB devices offered to consumers. With port replication and add-on hard drive controller cards there is hardly a limit on the size of its storage.
NAS appliances and gateways must be configured and managed using software tools that allow administrators to allocate space, manage RAID and storage behaviors, perform routine maintenance, and other tasks. Management software ideally provides interoperability with a variety of NAS devices from different vendors and can automate many of the routine