Definition: NAS gateway

A front end to storage that is highly scalable. A NAS gateway functions like a file server with unlimited storage. Unlike the traditional "legacy" NAS device, which contains the file sharing protocol, the file system and the drives, a NAS gateway has no drives.

The front end of the NAS gateway connects to the LAN over Ethernet. The back end connects to a RAID array via Fibre Channel or to a Fibre Channel switch, in which case the NAS gateway becomes a front end to a storage area network (SAN). Single RAID arrays can scale to several terabytes, but switches enable a large number of storage arrays to be attached.

Legacy NAS and NAS Gateways
When a traditional "legacy" NAS runs out of storage space or slows down due to a heavy workload, a new NAS device must be added to the network, and the file references in all the users' machines have to be remapped to the new drives. This administration headache is eliminated with a NAS gateway because it always presents users with a single folder interface to the storage. More storage can be added without reconfiguring anyone's computer. In addition, splitting a NAS system into gateways and storage arrays allows file processing and storage to be scaled independently of each other. See NAS and RAID.

A NAS Gateway

On the right side of this NAS gateway are two Fibre Channel ports for storage and four Gigabit Ethernet ports for LAN connectivity. The two 10/100 Ethernet sockets on the left are management ports. (Image courtesy of ONStor, Inc.)