Windows 2000: Revisiting Scalability

Almost two years to the day after its much-hyped and heavily criticized Scalability Day presentation, Microsoft Corp. again addressed scalability in a public forum.

DALLAS -- Almost two years to the day after its much-hyped and heavily criticized Scalability Day presentation, Microsoft Corp. again addressed scalability in a public forum. This time, Microsoft took another tack. The company unveiled to the Microsoft faithful at its annual TechEd users conference held here in late May a Web server farm tuned to produce a less-than-two-second response for 5,000 concurrent Web clients.

Where Scalability Day was a demonstration that used elaborate, highly customized systems built with not-yet-available technologies, this presentation was intended to depict a configuration using off-the-shelf components, providing users with take-home benefit. "The purpose was to arm developers with better information," explains Greg Leake, Visual Studio lead product manager at Microsoft.

Redmond tried to pre-empt criticism about its performance measurements by having the test results confirmed by the independent testing organization National Software Testing Laboratories (www.nstl.com). Microsoft also constructed a Web site to make publicly available the source code and other configuration parameters of the test suite (www.msdn.microsoft.com/vstudio/downloads/solutions.asp). Other information housed on the site includes Web resources, architecture guides, benchmark results and tuning guidelines.

The demonstration system was built on a three-tier architecture backed up by a two-way Compaq 6500R database server. In the middle tier, four quad-processor Compaq 6400R servers handled application logic, while 50 client machines used in the demo at TechEd -- 70 in the actual benchmark test -- provided the Web loading on the system. Microsoft used Windows NT Server 4.0, Enterprise Edition, on the servers, and used its Windows Load Balance Service (WLBS) product to distribute client requests across the four application logic servers.

The application logic was built by contract developer Vertigo Software Inc. (www.vertigosoftware.com) using COM objects generated from Visual Basic, and was described by Microsoft officials as a lower-performance configuration than had the logic been written in C++. Visual Basic was intentionally used to show that the system could perform well even when using tools that produce code that arguably is not optimal for best performance. The system was tested using a Web client loading program from RSW Software Inc. (www.rswsoftware.com) called e-Load testing suite.

Microsoft's Leake says the demonstration and the online scalability center is intended to serve as a resource for customers that may be looking to build their own scalable solutions. "[The Scalability Center's purpose] is getting information out to developers about our tools to help them make the right technology decisions, help them properly apply the right technology." A key point, he adds, is that, "The architecture mattered deeply."

To add credibility to its presentation, Microsoft invited a number of high-profile customers to discuss their own system configurations, including TV Guide Inc., NASDAQ and telecom giant QualComm Inc.

TV Guide is using WLBS to distribute Web traffic across 10 quad-processor Compaq 5500 Servers, each of which is running Windows NT Server 4.0, Enterprise Edition, and a replica of the site content. While the site traffic is somewhat difficult to predict due to the recent acquisition of TV Guide by Preview, the company is taking a conservative approach to sizing. "It's hard to predict traffic, [so] we wanted to come in over rather than under," explains Larry Scott, senior engineer at TV Guide. TV Guide's systems provide ASP-heavy content that pulls from a proprietary database, although there also is relatively little transactional activity.

For now, TV Guide is not planning to rush to Windows 2000, although the concept of server consolidation is appealing. According to Tim Demers, manager of product development for TV Guide Networks Inc., the company would consider server consolidation using an eight-way system. "If I could take an eight-by-800 [MHz] -- price justified -- we would [consolidate] and move a couple of our systems off to an auxiliary position," he says. Windows 2000 deployment will come when needs dictate it. The company has no preconceived notions for when the time to deploy will be right.

At the Code Division Multiple Access unit of QualComm, a project is under way to build a six-machine Web infrastructure to support a highly transactional secure site that will allow customers to track arrivals and deliveries of trucks from trucking contractors. The system presents data from QualComm's nation-wide vehicle tracking service in Web format from its San Diego headquarters.

The site includes a two-processor Web server, which is backed up by a formidable server farm that includes two quad-processor database servers, a two-way Xeon business logic server, an Exchange Server machine and another system used to report on and schedule system activities. The entire configuration is replicated at a second site located in Las Vegas, providing a redundant back up in the event of a serious outage at one of the sites.

Qualcomm uses a mix of application development technologies, including parts built in C++, Visual J++, Visual FoxPro and ASP components. "We were trying to leverage the skill set we have," explains Vik Yashpal, a senior software applications engineer at QualComm.

Microsoft's Leake says that longer term, Microsoft plans to produce other demonstrations, possibly covering other workload types such as transaction processing or message queuing -- also backed up by independent testing and downloadable code at its Web site.