A good e-business technical architecture makes it easy to scale up the software and the hardware to cope with increased loads at short notice. Demand on the Web can be unpredictable, and it's essential that the Web site doesn't crash at its most visible time. For example, florist Web sites must not get overloaded on Mother's Day or St. Valentine's Day, an auction site must not have poor response times when a popular TV show carries an article about it, and the e-marketplace with news features aimed at the farming community must not buckle under in the wake of a surge in demand due to a foot-and-mouth outbreak.
Capacity planning and load prediction can only work up to a point. Using load-balancing techniques for hardware and software can help a Web site to scale to meet demand. NT Load Balancing Services and Microsoft Clustering Services (Wolfpack) have now been incorporated into Windows 2000 Advanced Server. Jrun 3.0 Enterprise Edition includes a copy of ClusterCATS, which provides robust features for Web site availability, load balancing and failover services (see http://www.sys-con.com/java/archives/0512/Mitchko/index_e.html).