When Lightning Strikes

As Microsoft Corp.'s Windows NT server grows in popularity, major vendors have released a torrent of clustering solutions, which are either home-grown or based on Microsoft's own clustering technology. These new solutions provide federal users with a rich menu of choices at both the high and low ends of the market.

Clustering, however, continues to mean different things to different people. Typically, it means strapping together multiple servers as a way to protect against system failures, either of the operating system or the application or a combination. In the event that the primary system fails, the other system will pick up the workload so that users can work without interruption. It can involve a range from two to 16 servers and employ shared external storage systems, mirrored internal disks or selective application replication.

Despite all the products surfacing in the market, only 3 to 5 percent of all Windows NT nodes use some type of clustering, said Dan Dolan, an industry analyst with Dataquest, San Jose, Calif. But he expects at least 20 percent of Windows NT nodes to be clustered by 2002, especially with the advent of the "plug-and-play scenario," with out-of-the-box clusters offered by Dell Computer Corp., Data General Corp. and others.

Native Clustering

Although clustering solutions have been available for several years, Microsoft spurred the market with the introduction of its own Clustering Services technology late last year. It runs with Windows NT Enterprise Edition 4.0, bringing forth solutions from a large number of vendors and spurring considerable interest in the market.

Many people are looking at clustering in the federal market, said Sean Murphy, a senior systems engineer with Microsoft Federal, Washington, D.C. Clustered solutions running the Microsoft Exchange groupware application are already in production in the Department of Veterans Affairs and the Defense Intelligence Agency, Murphy said.

Microsoft's initial clustering release supports two server nodes. The company also offers "cluster-aware" versions of its SQL Server database software and Exchange applications, which are tailored to take advantage of the clustering capability.

Microsoft clustering uses shared external array storage. The servers share a small computer system interface bus to the external storage, so disk ownership can be transferred from one node to the other after a system failure. The servers also have a "heartbeat connection" over which they monitor each other's health.

The Microsoft offering is a good technology for high availability, but it is less powerful in some ways than solutions developed by other vendors, such as NCR Corp.'s LifeKeeper and Veritas Software Corp.'s Firstwatch products, Dolan said.

With Windows NT 5.0, Microsoft plans to support more clustered nodes. Although the company will not say how many nodes, industry rumors indicate it may be as many as 16.

Other expected features are easier setup, easier migration from a single system to a cluster, more features for load balancing, easier cluster updates, easier component hot swap and enhanced communications support, Murphy said.

Microsoft's introduction of clustering technology has not dampened the market for other solutions. Many vendors offer competing technology, although they sell Microsoft's as well.

Vinca Corp., Orem, Utah, is positioning its Co-StandbyServer for NT as an alternative for the low end of the market. Priced at $3,125, the software costs about twice as much as Microsoft's solution. But because of differences in the way that data is shared between servers, "we can use less-expensive hardware," said Art Dearing, director of Windows NT products and business development in Orem, Utah.

Specifically, Microsoft's use of shared external disk arrays is more expensive than Vinca's use of internal disk mirroring, the company said. Vinca also supports the less-expensive, standard Windows NT as well as Enterprise Edition, unlike Microsoft. "We're more applicable to the branch-office configuration," Dearing said.

Similarly, Digital Equipment Corp. offers its previous Digital Clusters solution as a fit at the low end; it is priced at less than $1,000 per node, said Paul Thuman, Digital's manager of Windows NT server sales, federal government, in Greenbelt, Md.

Still, Digital views the Microsoft technology as its "strategic clustering product," Thuman said, and the company offers a free software wizard that will guide Digital customers who want to move to Microsoft clustering. Digital recently sold 240 copies of Microsoft's clustering software to the VA, the company said.

Data General Corp. offers both Microsoft's clustering software and Veritas Software's FirstWatch, said Frank Kenney, director of Windows NT product marketing in Westboro, Mass. The rack- mounted Aviion NT Cluster-in-a-Box combines either Microsoft or FirstWatch fail-over clustering with Clariion Redundant Array of Independent Disks storage.

"We were the first ones with a complete solution," integrating hardware and software in one package, Kenney said. "If we didn't do this, the customer would get at least 15 boxes of stuff" to build a similar solution, he said. "The probability of something going wrong is very high."

Other vendors are targeting the high end of the market.

For example, NCR's LifeKeeper allows customers to cluster up to 16 eight-way Windows NT servers. Microsoft's technology "is targeted at entry-level clustering environments," said Kevin Noreen, NCR's product marketing manager in Columbia, S.C.

One NCR customer, the Army's Single Agency Manager office, provides communications switching for multiservice logistics and communications traffic, said Wunzell Steele, a vice president with NCR's Government Systems Corp., Rockville, Md. The SAM office uses a clustered pair of NCR's four-way WorldMark 4300 servers with LifeKeeper software.

Unisys Corp. plans to push Windows NT even higher. The company this spring announced its new Cellular MultiProcessing server architecture, which will make it possible to combine up to 32 processors as a large symmetric multiprocessing system or in up to eight internal clusters, thereby improving availability and performance. The first systems are slated for release early next year.

The architecture will be able to run both Windows NT and Unix in the same box, said Venkatapathi Puvvada, director of Enterprise Technologies with Unisys Federal Systems, McLean, Va. Unisys also plans to use second-generation Microsoft clustering, which he expects to include some support for applications scalability.

Early Adopters

Microsoft already has had some early success in the federal market with its clustering solutions.

As part of a Justice Department initiative called Community Oriented Policing Services Making Officer Redeployment Effective, the Washington, D.C., Metropolitan Police Department is using clustered Windows NT servers with native Microsoft clustering to support officers' wireless access to the FBI's National Crime Information Center database, said Deborah Wright, director of information systems for the Washington, D.C., police.

The wireless application, developed by GTE Government Systems, runs on fully redundant Hewlett-Packard Co. NetServer LX Pro servers running dual 200 MHz Intel Corp. Pentium processors, Wright said.

The police department has two applications, each backed by a Windows NT cluster pair. The Mobile Data Computers solution allows officers, using laptops in their patrol cars, to access the FBI database, using the Windows NT servers as a kind of message switch, said Paul Barsalou, GTE's program manager in Chantilly, Va. The second HP Windows NT cluster is supporting a records management system upgrade.

Other federal users have chosen non-Microsoft NT clustering solutions. The U.S. Transportation Command (Transcom) implemented five Windows NT cluster pairs as a subnode within the consolidated logistics command and control system known as the Joint Mobility Control Group, said Lt. Cmdr. John Jorgenson, who was program manager for the project until recently.

After a survey of Windows NT cluster offerings, Transcom selected Data General servers, using Firstwatch software. Microsoft's solution was unavailable at the time, Jorgenson said. But even after its release, the organization decided not to use it until it becomes more mature.

Other federal users have been less enthralled with Windows NT clustering.

NASA Lewis Research Center experimented with clustering for scientific and engineering computing applications two years ago with dual-bootable Windows NT/Linux operating systems, said Kim Johnson, team leader for the site's Advanced Computational Concepts Lab, Cleveland, Ohio. Linux is a freely distributed version of Unix.

The lab looked at Windows NT because the systems are less expensive and the "desktop application side is going the NT route," Johnson said. But the organization ultimately decided the Linux systems performed better than Windows NT and users were more comfortable with the Unix platform, Johnson said.

Application-Level Clustering

While most clustering solutions focus on providing high availability, Lotus Development Corp., Oracle Corp. and other software vendors have embraced server clustering as a way to improve application performance.

Lotus' Domino server clustering scales to six servers, supports mixed operating systems and provides dynamic load balancing as well as server fail-over, said Lori Fucarile, product manager for Domino Clusters for Lotus, Cambridge, Mass. Dynamic load balancing allows work to be distributed evenly across a cluster.

The Environmental Protection Agency, a major Lotus Notes and Windows NT user, expects to "go to clustering in a fairly large way," said George Hesselbacher, a computer systems analyst in the agency's Enterprise Systems Division. By taking advantage of clustering at the application level rather than operating system level, the EPA can support a mix of operating systems, Hesselbacher said.

Oracle, meanwhile, recently issued a second-generation version of its Parallel Server product. Although its largest certified cluster is a six-node Compaq offering, "we have 16 [nodes running] in the lab and will probably go to 32," said Larry Weiss, government Windows NT solutions manager for Oracle in Bethesda, Md. By the end of the year, IBM Corp. wants to certify a 16-node version running on its Netfinity Windows NT cluster, which could support 1 terabyte of data, Weiss said.

To make it easier for customers to run the Oracle software, Dell plans to ship high-end Windows NT servers with the database installed from the factory starting in late 1998 or early 1999, said Bob Van Steenberg, vice president of product and program management at Dell.

-- Adams is a free-lance writer based in Alexandria, Va.

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AT A GLANCE

Status: Although various clustering solutions for Windows NT services are available, Microsoft Corp.'s development of native Windows NT clustering technology has spurred activity in the market.

issues: The current release of Microsoft's Clustering Services is limited to two-node clusters, while other vendors' solutions scale higher. Also, other vendors are targeting organizations that need to support multiple operating systems in a cluster.

outlook: Very good. The market as a whole continues to push for greater functionality as the demand grows for high availability in Windows NT servers.