Network-Attached Storage (NAS) Device

Description

A NAS device is a Network Attached Storage device that is a server that is dedicated to nothing more than file sharing. It is the most complete networked storage solution, and the only type of networked storage that allows data sharing by connected host systems. Usually NAS devices consist of an interface as opposed to devices such as a mouse and keyboard, and are a preferred solution for enterprise applications and database environments.

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History


Early NAS Devices


Netware (1983)- a network operating system developed by Novell, Inc in 1983. It was one of the early NAS to use multitasking to run various services on a PC. This NOS <NETWORK operating="" system=""> was later called Novell NetWare. It was based on NCP Network Core Protocol which is a packet based protocol that allows clients to send and receive information from a NetWare server.

NFS (1984)- <NETWORK file="" system=""> was developed by Sun Microsystems in 1984. This allowed users to access information over a network as if the network devices were attached to its local disks. This system was built on the Open Network Computing Remote Procedure Call (NC RPC).

3Server-a headless dedicated network server machine designed to run 3Com LAN server software.

3+Share-introduced in the early 1980's this was a pioneering fille and print sharing product. It was a mulltitasking network server stack that ran on top of single-tasking MS-DOS. Internally, it had a network stack, file and print server modules, disk caching, user handling and more, all running simultaneously inside the DOS memory space. Because they were not limited by the PC memory map, 3+Share could support a megabyte or so of flat memory, breaking the PC's 640kb barrier. This was a large amount of RAM for the time.

LAN Manager-was an advanced Network Operating System (NOS) from Microsoft developed in cooperation with 3Com. It was designed to succeed 3Com's innovative 3+Share network server software which ran on top of MS-DOS.

Auspex Systems-was founded in 1987 by Larry Boucher, CEO of Adaptec, as a provider of network attached storage devices, a product category they invented. They became a leading provider of enterprise storage in the mid-1990s but fell behind Network Appliance in the field. The company was liquidated in 2003, with the patent portfolio going to Network Appliance and the services business to GlassHouse Technologies.

Network Appliance-Network Appliance is credited with the widespread adoption of Network Attached Storage or "NAS" and pioneered Unified Storage. Now Network Appliance storage products support a variety of storage protocols such as iSCSI SAN, Fibre Channel SAN, CIFS and NFS. The key technologies behind most of Network Appliance's product line are the Data ONTAP storage operating system and WAFL file system.

Exanet-founded in 2000, is a software company which provides network-attached storage software solutions. Exanet storage system solutions are hardware independent. Their NAS software storage solution provides single file system scalability, and is compatible with Linux, Mac, and PC computer systems.


Benefits


NAS Device offers benefits that are not available in DAS and SANs storage systems.

1. Better speed and stability due to 100% dedicated file sharing.
2. NAS devices are cheaper and easier to maintain and install.
3. Data can be shared over multiple servers.
4. If multiple devices are used, they can be centralized and made more efficient.

Drawbacks


Limitations can occur if the NAS becomes occupied with too many users, too many I/O operations, or CPU processing power that is too demanding for the device. A server system is easily upgraded by adding one or more servers into a cluster, upgrading the CPU power, while the NAS is limited to its own hardware, which is in most cases is not upgradeable.

NAS devices will also fail to expose well-known services that are typical of a file server, or enable them in a way that is not efficient. An example would be the inability to index a file quickly or the ability to calculate disk usage of separate directories.

Security of the NAS can also be an issue. NAS drives are generally safe to place on a network if connected to the Internet, however there are some security concerns that need to be addressed by administrators. Some NAS drives are based on a Linux operating system and are open source. There are a numerous firmware upgrades on the Internet produced by various sources and NAS drive users often upgrade their firmware to overcome problems and issues they have experienced. Unintentionally extra features may be added that can change the security of the NAS drive and network.

NAS Uses


NAS allows a network to utilize more hard disk storage space without turning off the servers it uses when they are in need of repair and updates. Storage is not a principal function of a server when an NAS device is employed. The server is freed up to process data and the NAS device transports this device to the user. This is known as a storage-centric design.

Beyond general centralized storage in environments with abundant data, NAS, by providing storage space, can add to the capabilities of less expensive and less elaborate systems, including load balancing and fault tolerant email. The consumer-market has begun to desire NAS for use in conjunction with large amounts of multimedia data. Consumer market appliances are already available and are more convenient than their bulky rack mounted counterparts. NAS devices are becoming more and more affordable and offer similar performance to external hard drives such as USB and FireWire, for just a slightly greater cost than these out dated technologies. Several of these home consumer devices, including Buffalo’s TeraStation and Linksys NSLU2, are built around processors running an embedded Linux. These processors include; ARM PowerPC or MIPS. Universal Plug and Play protocol has recently been added to the capabilities list, this makes it possible for NAS to support the expanding array of networked home media players.

Citations

http://en.wikipedia.org/wiki/Network-attached_storage
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