server, which finally delivers the full page to the browser. The browser may then initiate several subsequent Http rEqueSts to retrieve the embedded(static) page For any given Web-based application, a large percentage of dynamic requests are made for identical or similar content, meaning that repeated requests for dnamic pages place a significant strain on application infrastructure. The higher the user load, the more accentuated the inefficiencies. To deal with this challenge, IT managers need state of-the-art caching and compression mechanisms that enable more efficient use of existing, low-cost hardware Peak Loads, Flash Crowds, Lights Out Considering the runtime, disk I/O, and network operations just described, one can appreciate how the computational overhead associated with building pages"on the for thousands of concurrent users can result in increasing delays and failures in data delivery. Many enterprise data centers try to counter this problem by addin more servers to their existing architectures. In order to sustain performance under ever-mounting loads, a successful CIO may need to multiply her investment in hardware and software by a factor of ten or more on a yearly basis. Capital outlay of such inordinate magnitude is not unheard of, and many online businesses and enterprise IT' departments have disproportionately large data center infrastructures for this reason But capacity planning is not a simple task. Even very large application infrastructures sometimes fail to produce the scalability, availability, and response time service levels demanded by a growing customer base, as illustrated by a number of high-profile Web site outages over the past few years. Not only is the number of Internet and enterprise users increasing, but also the volume and frequency of denial-of-service attacks are on the rise. The days when hardware companies offered free equipment to high-profile dotcom startups are long gone. In todays profit-conscious economy, the ultimate challeng for software developers and systems managers is to make dynamic applications perform and scale while at the same time lowering the infrastructure costs required to meet capacity targets. Caching and compression can help, but IT managers also need sophisticated workload management tools at their disposal in order to cost effectively contain flash crowds and other unexpected surges in traffic The End User is King End users expect Web-based applications to be fast. A 2001 Zona Research report entitled The Need for Speed II highlights the importance of adhering to what has become known as the"eight second rule": if consumers cannot download a Wel page within eight seconds, they may jump to a competitor's site or take their business off the Web entirely. With regard to the economic impact of slow Web sites, Zona finds"more than $25 billion [annually] in potential lost business due to Web performance issues. 2 Zona Research, Tbe Need for Speed ll, April 200 OracleAS Web Cache 10g(10.1.2)-Technical White Pape poration, All Rights ReservedPage 6 OracleAS Web Cache 10g (10.1.2) -- Technical White Paper Copyright © 1999-2005 Oracle Corporation, All Rights Reserved server, which finally delivers the full page to the browser. The browser may then initiate several subsequent HTTP requests to retrieve the embedded (static) page elements. For any given Web-based application, a large percentage of dynamic requests are made for identical or similar content, meaning that repeated requests for dynamic pages place a significant strain on application infrastructure. The higher the user load, the more accentuated the inefficiencies. To deal with this challenge, IT managers need state￾of-the-art caching and compression mechanisms that enable more efficient use of existing, low-cost hardware. Peak Loads, Flash Crowds, Lights Out Considering the runtime, disk I/O, and network operations just described, one can appreciate how the computational overhead associated with building pages “on the fly” for thousands of concurrent users can result in increasing delays and failures in data delivery. Many enterprise data centers try to counter this problem by adding more servers to their existing architectures. In order to sustain performance under ever-mounting loads, a successful CIO may need to multiply her investment in hardware and software by a factor of ten or more on a yearly basis. Capital outlay of such inordinate magnitude is not unheard of, and many online businesses and enterprise IT departments have disproportionately large data center infrastructures for this reason. But capacity planning is not a simple task. Even very large application infrastructures sometimes fail to produce the scalability, availability, and response time service levels demanded by a growing customer base, as illustrated by a number of high-profile Web site outages over the past few years. Not only is the number of Internet and enterprise users increasing, but also the volume and frequency of denial-of-service attacks are on the rise. The days when hardware companies offered free equipment to high-profile dotcom startups are long gone. In today’s profit-conscious economy, the ultimate challenge for software developers and systems managers is to make dynamic applications perform and scale while at the same time lowering the infrastructure costs required to meet capacity targets. Caching and compression can help, but IT managers also need sophisticated workload management tools at their disposal in order to cost￾effectively contain flash crowds and other unexpected surges in traffic. The End User is King End users expect Web-based applications to be fast. A 2001 Zona Research report entitled The Need for Speed II highlights the importance of adhering to what has become known as the “eight second rule”: if consumers cannot download a Web page within eight seconds, they may jump to a competitor’s site or take their business off the Web entirely. With regard to the economic impact of slow Web sites, Zona finds “more than $25 billion [annually] in potential lost business due to Web performance issues.”2 2 Zona Research, The Need for Speed II, April 2001