InformationWeek

August 11, 1997

Price Drop Makes NT Clusters Viable

Small and midsize users see alternative to Unix-based or proprietary solutions

By Richard Adhikari

hen Robert Hill wanted to implement some new applications, he found his existing Windows NT server was maxed out. Hill, the IT manager at CareAmerica Health Plans Inc., was worried. The high-availability systems he would need had always been too expensive.

But when he began investigating and discovered that Windows NT clusters have dropped in price enough to fit his budget, Hill selected a two-server cluster from Digital Equipment. The cluster has been running in production since March, and CareAmerica is adding new applications as needed.

As recently a s three years ago, clustered servers would not have been an option. Prices were too high for any companies except those that absolutely needed fault tolerance, such as banks. Prices for proprietary clustered solutions, such as those from Pyramid Technology and Tandem Computers, began in the six-figure range. Similarly, large Unix clusters generally ran more than $100,000 for hardware and software.

Today, Windows NT clustering solutions from third parties have changed all that. Not only is the NT operating system less expensive than Unix, but so is the clustering software. It costs slightly more than $23,000 for a low-end two-node Wolfpack package from Microsoft, compared with about $50,000 for Unix clustering software, according to Joe Barkan, a research director at Gartner Group Inc., an IT advisory firm in Stamford, Conn. Also, the cost of peripherals such as network interface cards (NICs) is much lower for the PC platform, on which NT runs. In fact, third-party NT clustering software solutions will re main inexpensive even though the price of NT Enterprise Edition, into which Microsoft will bundle its Wolfpack clustering software, is rising. Finally, NT clustering and Wolfpack are first-generation technologies, while Unix and host clustering are mature.

More Than Unix
Lower prices aren't the only factor spurring many IS managers to implement NT server clusters. Some managers want vendor independence, which isn't available with Unix solutions. Still others go to Windows NT clusters because they want to make better use of corporate technology. They're well aware that Windows NT is not as scalable as Unix and proprietary solutions (NT clusters are limited to simple uses such as file and print server setups, and as application servers). However, they contend that the low pricing of NT cluster technology lets them offer high availability even in applications that are not crucial.

Also, vendors that offer Windows NT server clusters have pledged support for the Microsoft Wolfpack API. Th ey'll provide migration paths to Wolfpack when the two-node Wolfpack cluster is released in Windows NT Server Enterprise Edition later this summer. In contrast, there are no standards for Unix and proprietary clustering solutions.

One way to get the most out of NT server clusters is to use them in departments, says Ed Schaider, VP at the Standish Group International Inc., a consulting firm in Los Gatos, Calif. NT automatically reboots the server every time an application is brought online. In an enterprise environment, this means everyone on the server will go down. "The correct approach is to contain the NT cluster where the damage it can do is not enterprisewide but departmental, so you only have a couple of users affected," Schaider says. "NT makes a lot of sense at the departmental level, where you can host NT clusters off your larger network."

The limitations of NT clusters don't bother Hill of CareAmerica Health Plans, in Woodland Hills, Calif. Hill realizes proprietary NT clusters aren't "rea l high-end bulletproof systems" that users can run their most important applications on. But, he adds, they suit small and medium-sized companies such as his because they're "inexpensive, easy to use, and fairly reliable." CareAmerica, which is privately held, has about 265,000 members, and its revenue last year hit nearly $630 million.

CareAmerica's server cluster consists of two Digital Prioris ZX-6200s, each running two 200-MHz Pentium Pros linked by Digital Clusters software. Each server has 512 Kbytes of cache, 256 Mbytes of RAM, and four 2-Gbyte hard drives. They also share external storage: the RAID (redundant array of independent disks) Array 410 by Digital Equipment's StorageWorks unit, which contains 16 hard drives of 4.3-Gbyte capacity each, in a RAID 5 array. Both servers run Microsoft SQL Server 6.5 and Digital Clustering 1.1 under Windows NT 4.0. If one server fails, the other takes over its workload without interruption to end users.

For all that hardware, software, operating system, a nd upgrade from Microsoft SQL Server 4.2.1, Hill paid $93,000. He says that's a lot cheaper to purchase, implement, and maintain than the Sun Microsystems cluster solution he also looked at.

At MediaTel Corp., a San Francisco provider of electronic document-delivery services, third-party NT clusters are expected to help the company manage incremental growth. MediaTel sends time-sensitive, business-to-business fax broadcasts on behalf of its clients. Thomas Ryan, the company's VP of engineering, says the firm transmits 500,000 to 750,000 documents daily, round the clock, and has 200 T1 1.544-Mbps lines. Documents sent in by clients are faxed from one of several hubs around the country that act as giant fax machines. The hubs consist of single-CPU Hewlett-Packard LX Pro-166 servers running the Btrieve database over Novell NetWare 3.1.2, linked by 100Base-T Ethernet. Each server has four NICs.

Ryan says MediaTel, founded in 1989, is growing by 40% to 50% a year, and he may bring up more hubs. He wants to replace the HP servers with NT server clusters because they offer high availability, which single-CPU boxes don't. Unix server clusters are out because "Unix doesn't quite give you the cross-platform hardware independence we want," but NT runs on any vendor's PC platform, Ryan adds. He's evaluating a two-node cluster from Tandem consisting of the latest system that Tandem is set to officially unveil this week.

At Scott Air Force Base, outside St. Louis, Lt. Cmdr. John Jorgensen, a program manager, is moving to Windows NT server clusters to reduce technological overkill. Jorgensen works for the U.S. Transportation Command, which handles transportation logistics worldwide for the Department of Defense.

That's a lot of moving-on any given day, 3,000 to 15,000 moves take place worldwide, depending on various factors. Staff at the command's headquarters use a LAN made up of Sun workstations running Solaris at the front end linked by fiber-optic lines to Sun servers running databases on the back end. T his system has "enough power to run several small Third World countries," Jorgensen says. Users have way too much machine for their needs-they are preparing presentations and creating word-processing files on the workstations. "It's like driving a Corvette to the grocery store," Jorgensen says.

So Jorgensen is replacing the front-end workstations with PCs and adding Windows NT server clusters to the back end for user management and file- and print-management. He'll continue running the databases on the Sun servers: a SparcStation 2000, several SparcStation 1000s, and some SparcStation 20s.

Jorgensen bought five two-node clusters from Data General Corp. in Westboro, Mass. Nine of the servers are DG 2600s, and the tenth is a DG 3600, all using FirstWatch NT clustering software DG licensed from Veritas Corp. "I wanted what Wolfpack promises but doesn't do yet, and I want to do it right now, so I got FirstWatch," Jorgensen says.

The bottom line on low-cost server clusters: Use them for what they can offer, which is failover and reliability at a relatively low price for nonessential applications. Don't expect NT clusters to compete with high-end Unix or proprietary ones. At least for now.

See related story " NT Clusters--Try Before You Buy "

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