But can NAS do databases?

One of the longstanding knocks on network-attached storage — as opposed to traditional server-attached storage — was that it was fine for storing occasionally used data such as word processing or computer-aided design files, but not for more frequently accessed, transaction-oriented database files. That reputation is starting to change.

One of the arguments against using NAS for database storage was that it would tie up the local-area network with lots of traffic as servers accessed the database. That concern is disappearing as more agencies deploy very fast switched networks and Gigabit Ethernet backbones, which can better handle the heavier traffic. New database designs also help.

"Oracle [Corp.] and other database vendors decided to bypass the normal file system and go out and write blocks of their own directly to disk for efficiency and performance reasons," said David Hill, research director for storage and storage management with Aberdeen Group Inc. in Boston.

More fault-tolerant NAS designs — such as redundant internal components, clustering solutions to provide failover protection and online disaster recovery software — are also increasing people's comfort level with using NAS for databases and as primary storage devices.

An executive at NAS market pioneer Network Appliance Inc. said that about 20 percent of its business is with customers using NAS for database applications. For example, IT officials at the U.S. Air Force's Air Reserve Personnel Center in Denver just bought one of the company's NAS filers to store, among other types of files, the database for the center's Microsoft Corp. Exchange e-mail application.

Lt. Col. Frederick "Bud" Bromley III, deputy director of communications and information at the Air Reserve Personnel Center, said he might consider also using NAS to store a relational database that supports the center's customer relationship management application if that database begins to grow very quickly.

Even with these developments, Aberdeen's Hill said NAS still has some limitations. "You're obviously not going to put a very information-intensive online-transaction processing system on there, such as an airline reservation system," he said. "But as NAS has matured, its ability to handle databases has improved to give reasonable performance."