Network-attached storage (NAS) is a type of dedicated file storage device that provides local area network (LAN) nodes with file-based shared storage through a standard Ethernet connection. NAS devices, which typically do not have a keyboard or display, are configured and managed with a browser-based utility program. Each NAS device resides on the LAN as an independent network node and has its own IP address.
Network-attached storage can provide multiple clients on the network with access to the same files. NAS devices can also be clustered together to provide both vertical and horizontal scalability. Clustering provides access to all files from any of the clustered nodes, regardless of the physical location of the file. Enterprises may use a NAS array as a backup target for archiving and disaster recovery. Some higher-end NAS products can hold enough disks to support RAID (redundant array of independent disks) technology, combining multiple hard disks into one logical unit to improve speed, high availability and redundancy. Many NAS vendors provide an extra layer of redundancy by automatically backing up files to cloud-based storage. NAS products may also support virtualization, data deduplication, flash storage, multiprotocol access and replication.
While NAS handles input/output (I/O) requests for individual files, a storage-area network (SAN) manages I/O requests for contiguous blocks of data or block storage. Unlike NAS, most SANs use the Fibre Channel protocol for high-speed data transport rather than Ethernet. Enterprises that need to unify the management of file-, block- and object-level storage may use a software-defined storage solution such as SUSE Enterprise Storage.