A Scalability Metric Research Of Web Application System

As the rapid development of network technology and Web technology, the Web-based applications have developed from simple Web site to professional applications, e-commerce as well as large-scale enterprise-class information systems. In the rapid development of Web applications, it not only requires the system to complete the functions that should have, but the system performance requirements have become more sophisticated. Because web applications run on Internet/Intranet environment, we can not control the number of visiting users and the network performance. If the system can not provide an acceptable and stable performance, the system's processing capabilities will inevitably reduce, and even lose many customers, give companies a tremendous impact on market competition. Scalability is an important aspect of system performance, when the business volume and the number of users sharply increase, whether the system's response time can maintain a linear growth in the larger load and the system will appear an unacceptable situation or not. As the high load in the test experiments is often difficult to achieve, the method discussed in this article can predict the performance of a larger load, by collecting and analyzing performance data in smaller load.In the field of parallel computing, there are more researches about scalability. In the Web application systems, people are standing on the developer's point of view to discuss the scalability, but the users do not understand the system architecture, they concern whether the system can produce more benefits when put in certain investment. That is, whether the system can do more things, such as respond to more users'requests, implement more work, or handle more data, and whether the response efficiency is high reliability. In this article, we stand on the users'point of view, to measure the scalability of Web application system, use a simple and effective way to test whether a system can fulfill the users'performance requirements.In this paper, the following aspects were discussed: (?) Introduce scalability Research in internal and abroad, including measurement methods in the field of parallel computing, distributed systems, and the technologies to improve scalability in the field of Web applications.(?) Introduce the related concepts of software measurement, software metrics, and the methods of data collection.(?) According to the features of Web applications, it presents the definition of Web application scalability, describes the Measurement with the formal method.(?) Build a metric sub-model to analyze the elements that are used to calculate scalability.(?) Develop a Scalability Analysis System (SAS) for automated analyzing the scalability.(?) Do performance testing for a real Web application to collect data. Use the method proposed in this paper to analyze its scalability, then verify the effectiveness of the method.(?) In this article concluded with a brief summary and outlook, also given in this article has yet to be resolved and research problems.