According to whatis.com, NAS is hard disk storage that is set up with its own network address rather than being attached to the department computer.NAS consists of hard disk storage and software for mapping file locations to the network-attached device. NAS can be a step toward and included as part of a SAN.
NAS hardware comes in the form of a standalone file server or a NAS head. A NAS standalone system includes a NAS controller and a storage array. Data is stored in CIFS or NFS file systems and can be shared across networks. A NAS head – also known as a NAS gateway – provides a NAS controller, but customers use existing storage arrays for disk capacity. With a NAS head, users can use part of an array for NAS and the rest of the array for SAN-based storage.Key vendors and products
There are many players in the NAS hardware market: the most well-known being Network Appliance Inc. and EMC Corp. Vendors such as Adaptec Inc. (which recently acquired Snap Appliance), Dell Inc. and Procom Technology are serving the lower end of the NAS market.According to Tony Asaro, senior analyst at Enterprise Strategy Group, Milford, Mass., the NAS market is rife with startups developing unique technologies. He mentioned BlueArc Corp., with its scalable Titan Silicon Storage Server and Isilon Systems Inc., with its Isilon IQ appliance and clustered network architecture. Asaro also highlighted Silicon Graphics Inc., ONStor Inc., Exanet, Polyserve Inc. and Panasas Inc. as emerging NAS players that offer scalable file systems. Who's not keeping up in NAS? "The folks that are slipping include large storage vendors like HDS, HP, IBM and Sun," Asaro said. "In many cases, these vendors have a decent revenue stream compared to the emerging vendors and startups, but given their positions in the market, they all should be doing much better." Innovations and trends
Recent innovations around NAS, according to Asaro, are the ability to create clusters of more than two controllers and allowing users to scale as needed. Another innovation is the scalability of the file systems themselves. This is where startups with scalable file systems have an advantage, Asaro said."Traditional NAS vendors like NetApp and EMC are limited to 16 terabytes (TB) and 2 TB, respectively, while newer systems can scale to 100 TB file systems and beyond," he said. Randy Kerns, senior partner at the Evaluator Group, Greenwood Village, Colo., sees innovation coming from NetApp's acquisition of Spinnaker, whose SpinOS distributed operating system allows users to manage multiple NAS boxes like they are one box. "This is a unique opportunity to move NAS to a grid storage approach," he said. In a similar vein, Asaro points to file virtualization as an up-and-coming NAS innovation, with Acopia Networks Inc. and Rainfinity as two vendors making noise in this space. "With file virtualization, users can aggregate multiple file systems with existing NAS systems for better performance and easier management," Asaro said.
Kerns added that vendors are putting TCP/IP accelerators (offload engines) into NAS boxes to improve performance and most now have point-in-time copy and remote copy features.One key area in NAS that is still developing, according to Kerns, is the use of global namespaces to manage multiple file servers under one umbrella.
This article orginally appeared on SearchStorage.com.