InformationWeek
Defining The Business Value Of Technology
August 23, 1999
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Behind the friendly face of many Web sites is a sophisticated system for maintaining peak performance
By Jason Levitt
Raw performance of Web application servers, http servers, and databases is the key to customer satisfaction and future scalability. Slow response times are frustrating to users and can impact the flow of data through the transaction-processing pipeline, affecting other components of your back office, including network connections. Nevertheless, for E-commerce sites dealing with thousands of Web application users at any given moment while also dispensing hundreds of thousands of unique page views per day, achieving peak performance and allowing for future growth is a somewhat mysterious art. "You have to design everything as a system," says Gary Roach, software architect for systems integrator Tensor Information Systems, who has worked on sites for the U.S. Postal Service, airline reservations provider Sabre Inc., and Consumer Digest magazine. "You can't design the application without regard to the database. You have to have everything working in a partnership."
Typically, larger E-commerce sites have developed their own custom solutions, sometimes in conjunction with commercial tools and shrink-wrapped applications, but other times--when appropriate tools aren't available--from scratch. "It's appalling that we have to do this," says Andy Martin, chief technology officer of Garden.com, referring to sophisticated caching schemes the online garden retailer had to implement to get good results from its Oracle database. "Oracle should be providing these low-level performance enhancements. We had to invent this stuff just to get the performance we needed. If we turn off our caching, you really notice the performance slowing down."
Interestingly, while database access techniques and Web application performance are important at many E-commerce sites, the size of Web pages, particularly when graphics and ad banners are included, is most often cited as the biggest performance bottleneck. "The slowest thing is getting graphic objects to the users' browsers," says Roach, who recently designed the Consumer Digest site using Apple's WebObjects.
Through Visual Studio, Microsoft is starting to score big wins with large, successful online sites such as audio-video provider Broadcast.com and Dell Online. Both run largely on Windows DNA (Distributed Network Architecture) products such as the Windows NT Server operating system and the SQL Server database.
Dell Online, previously called Dell.com, runs almost entirely on Microsoft DNA products. Microsoft's IIS Web server, Active Server Pages, and SQL Server are the foundation of the application server and database, and the site relies heavily on Microsoft's COM architecture and pieces from Microsoft's Site Server Commerce Edition. But Site Server Commerce Edition is more of a toolkit than a shrink-wrapped solution, so, like most large sites, Dell has had to craft solutions from the pieces. The Dell E-commerce site consists of 75-plus Dell PowerEdge servers, each with one or two processors and anywhere from 256 Mbps to 2 Gbps of RAM. With anywhere from 3,000 to 4,000 simultaneous shoppers visiting the online store at peak hours, Dell has had to craft solutions that can maintain the state of customer transactions in the event of system failures.
Illustration by Jane Marinsky/SIS
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he face of large electronic-commerce Web sites is deceptively simple. The friendly Web pages of bookseller Amazon. com or PC retailer Dell Online hide the fact that huge, pulsating server farms with sophisticated load balancing and fault tolerance are quickly brokering your Web clicks through a maze of database accesses, cached data, and network routes.
Consumer Digest runs 50 instances of the same Web application in order to parallel-process user requests from the Internet and caches all graphic elements on the front-end Apache http server instead of in the database. Though the 100-Mbit network connection between its application server and the Web server proves adequate at the Consumer Digest site, Web applications can be more robust than their network connections, sometimes filling up all available network bandwidth. "Customers should be aware--and it's not that hard to do--that they can create an application that will run so fast on Pentium-class hardware that they can saturate the network before the database or the application server become saturated," says Lloyd Arrow, a product manager for Microsoft's Visual Studio.
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Photo by Bill Kennedy
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