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Storage area networks find room to grow

This offers a good overview with some of the main pros and cons related to SAN adoption.

Networked storage

Storage area networks find room to grow

The information age presents network managers with a daunting challenge: store ever-increasing amounts of business-critical data, keep it secure but accessible at high speeds to multiple users, and ensure timely, regular backup -- all without increasing IT costs. Some companies see storage area networks as a solution.

by Garry Kranz

As companies grapple to store and protect vaster amounts of data, storage area networks (SAN) are gaining momentum. A SAN is a dedicated configuration of multiple servers connected to peripheral storage devices using high-speed fiber and special routers, switches and hubs. A SAN, usually part of an enterprise's overall computing resources, enables enterprises to consolidate data from disparate servers on to a centrally managed storage network.

Storage area networks offer certain key advantages over file serving and network-attached storage (NAS) boxes, namely improved data sharing, convenient storage expansion, remote backup and recovery and increased uptime.

But the adoption rate of SANs has been slowed by drawbacks such as high cost, interoperability of software, hardware and components and data security concerns.

The Pros

Data Sharing.
A SAN makes stored data available to multiple users simultaneously, without disrupting productivity. "A SAN provides high-speed access to data among a number of system servers, thus enabling data to be retrieved faster when used by a large number of users," says Dave Howard, chief executive officer at 1Vision Software Inc. in Loveland, Colo. "This is critical for efficient company operations and for Web storage where millions of users may need to access data."

Individual computers in a SAN see each data-storage device as a shared resource, eliminating data bottlenecks common to NAS and file serving environments. "You might have 20 computers, but each one sees the storage as one big pool," says Fabrice Helliker, a London-based vice president of engineering for BakBone Software, headquartered in San Diego, Calif.

Live expansion capacity.
A SAN allows network administrators to expand storage capacity without shutting down critical file servers. Instead, new storage devices are plugged directly into the fiber connecting the various servers to existing storage capacity.

"With the Internet, system administrators have to make sure their data is available all the time -- and keep it safe to boot," says Christopher Poelker, a storage architect with Hitachi Data Systems in New York City.

Remote backup and recovery.
Since it's a separate network, a SAN enables automatic data backup, meaning IT administrators don't need to swap out backup tapes each day. Backup occurs without interrupting users on other company computer networks. "One of the complaints of companies [using NAS boxes] is that backup traffic is consuming too much bandwidth from their production networks," says Lee Abrahamson, manager of SAN consulting for storage networking specialist CNT in Minneapolis, Minn.

A SAN also makes data migration more manageable. Data is transported across a high-speed fiber and stored on a remote server. "This eliminates the need to store data on the hard drive of individual machines," says Jim Rodriguez, senior security consultant with Atlanta-based Crescendo Technologies. It also makes data recovery easier if there's a disaster.

The Cons

Industry experts say a comprehensive SAN could cost hundreds of thousands of dollars, putting them beyond the reach of most small enterprises. Although a SAN could yield savings through the need for fewer IT professionals, the upfront cost intimidates most companies.

Some small and medium-size enterprises might want to build miniature SANs, consisting of a few switches on the network, for specific departments and applications. These smaller networks give you a head start and can be expanded later to accommodate your computing needs.

Interoperability also is a drawback. Companies implementing a SAN often buy hardware from one company, software from another company, while a third company supplies the components needed to connect everything together. "There is no overarching standard for SANs right now," notes Howard. "A lot of vendors make a single component, so companies need to be careful that the components they select are compatible with their system."

The Storage Networking Industry Association of Mountain View, Calif., is promoting open standards to ensure that different vendors' storage networking product products work compatibly. But the association concedes open standards are at least a year or two away.

Network security.
The lack of industry standards also heightens concern about security and the ability to prevent unauthorized access to data. Several workable options exist, including hybrid systems that use newer technology with more established architectures. Enterprise Storage Group of Milford, Mass., claims that concern about security is the chief impediment to widespread implementation of SANs.

Security safeguards should be built into a SAN, says Bill Van Emburg, chairman of Piscataway, N.J.-based systems integrator Quadrix Solutions Inc. "A SAN really is no different than any other computer network. The same need to separate different kinds of machines so that they can't be used to leverage each other's access still exists," says Van Emburg.

Who's Using SANs?
Despite the economies of scale they offer, cost and technical complexity have kept adoption rates of SANs low. It is estimated only 5-10 percent of Fortune 500 companies have installed SANs. The rate among smaller and medium-size enterprises is much lower. In a few years, however, SANs could become a necessity for all organizations with growing data storage demands, especially given the projected growth of e-commerce. "Before SANs, the choice was to add more storage capacity to a single server," says David Hill, a storage analyst with Boston-based Aberdeen Group. "But no longer it is enough to throw more space at a storage problem. The key is to manage space more effectively, because the one thing companies can't afford to be is: down."

Garry Kranz is a freelance business and technology writer based in Richmond, Va.


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