Some readers have been saying I don't give network-attached storage a fair showing as a viable option for storage consolidation and data growth management. For those of you who feel this way, this one's for you.
The origins of NAS came about in the mid-'80s, when companies were taking the power of the computer out to the desktop, out to the employees who were using the tools. With all that power going out to users, a problem arose: How do the users working on the same projects share common files in this newly distributed environment? Well, at first users would copy files over a network. Besides creating a huge versioning problem, users were complaining they needed more disk space to hold all these versions - and, by the way, my computer just crashed and I have no way to get that data back.
To begin to solve these problems, a then-small company named Sun started putting Network File System (NFS) out into the public domain. The whole idea behind NFS was to create pools of storage specifically for the purpose of sharing common files and easing some of the management (read: data protection) issues. NFS, while it has evolved over the years, is still the primary mechanism for sharing files in the Unix environment (as Microsoft's Common Internet File System is for Windows).
For many years, IT professionals used standard Unix systems to provide NFS services to their users, but there were problems. Back in the '80s and early '90s, networks, as well as systems, were not as reliable as they have become today. If a network or server failed, users would not have access to their data for hours.
Plus, Unix servers large enough to support large amounts of disk storage were expensive. Because of their cost, often other applications were run on those servers to get the best bang for the buck. Unfortunately, for the distributed users of the data, this caused performance degradation when accessing networked files.
The third issue with NFS servers was that management of the server and storage was not trivial. In the early days of NFS, there was little-to-no automation of management tasks. People had to be hired to baby-sit backups, mounting and unmounting tapes.
To solve the issues of the price and performance and management, NAS appliances came on the scene. Highly specialized servers designed to increase file access performance and support large amounts of storage started to appear. Because these appliances were so specialized, the amount of configuration information required by administrators was drastically reduced, making integration into an existing infrastructure trivial. By this time, automation of backup and recovery was being exploited to reduce the amount of human intervention required.
Today, NAS appliance companies like NetworkAppliance have simplified configuration options, significantly reducing the amount of time it takes to install a new NAS appliance onto your network. Most installations range in time from about 2 minutes to 10 minutes. Once the appliance is installed that space is available to authorized users for sharing files from both Unix and Windows.
Today, NAS is the easiest way to consolidate storage on a network. However, there are some drawbacks. NAS appliances use the NFS and CIFS protocols to share data over Ethernet. The time it takes to process these protocols causes latency when accessing networked storage. In addition, the data movement is subject to network bottlenecks if bandwidth is not closely monitored. Applications that are highly sensitive to latency, like database applications, cannot perform at their peak when accessing data from NAS appliances. With the advent of Gigabit Ethernet - and soon, 10 Gigabit Ethernet - many of these bandwidth issues will subside.
Finally, the scalability of an individual NAS appliance today is somewhat limited. Because the NAS appliance is, in effect, a server with direct attached storage behind it, once you have reached the limits of that appliance, another appliance must be purchased. This can become expensive as well as difficult when managing many of these NAS elements on your network. This issue has been addressed by some of the companies producing NAS appliances, like EMC, who see the NAS appliance as a server that can be serviced by a storage-area network.
Today, consolidation of files onto NAS appliances is the first and easiest step in easing some of the pains associated with the rapid growth of files being shared by multiple hosts. A plethora of NAS appliances are available today, ranging in price and capabilities, to meet your storage consolidation needs.
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Anne Skamarock is senior analyst with Enterprise Management Associates in Boulder, Colo., an analyst and market research firm focusing exclusively on enterprise management. She can be reached via e-mail.
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Past newsletters.
Network World, 05/14/01
