Scaling for E-Business

12.3. Traffic Bursts

There are two obvious questions that people like to ask about hurricanes: "Is it coming my way?" and "How strong is it?" In electronic business, similar questions arise very often: "Is the site going to receive a burst of hits?" and "How strong will the burst be?" Existing techniques and surveys can be used to answer the first question. But online companies need more information. They need to know how much computing and network capacity needs to be provisioned to support a traffic spike of a given intensity.

Web traffic is quite bursty [4]. Figure 12.2 shows the daily traffic to a real online retailer store. The upper part of the figure shows the hourly volume of hits for a typical week. One observation is that the number ...