Building Responsive and Scalable Web Applications

Responsiveness and scalability are important quality-of-service attributes for Web applications. Web sites that are slow, either because of poor responsiveness or lack of scalability, can produce customer dissatisfaction, loss of revenue and/or productivity, and potentially more serious consequences. To avoid these problems, it is important to know whether users will be able to access information in a timely fashion, whether the hardware will be able to handle the load, and whether the system will scale to meet projected demand before the system is deployed. This paper describes how to apply the techniques of Software Performance Engineering (SPE) to Web applications. We focus on using the SPE models to provide decision support during the software architectural design phase because the decisions made at that time have the largest effect on performance and scalability. A case study illustrates the application of these techniques to a typical Web application.