A Self-Adaptive Proportional Delay DifferServ Model for Heterogeneous Web Server Clusters
Manwu Xu · Dianzi xuebao · 2007
With the development of Internet technology,the Web Service is playing a more and more important role in satisfying the needs of large and growing community,this in turn demands that Web Servers meet the high QoS(Quality of Service) requirements of applications.In particular,Web Servers needs to deal with problems as highly concurrent requests,different clients with different QoS requirements,and so on.Therefore,how to improve the QoS of Web Servers has become a hot research topic.This paper presents a new proportional delay differserv-enabled model for heterogeneous Web Server clusters.The model describes the request arriving and serving process of cluster nodes by :[∞/∞/FCFS] queuing theory.The paper also puts forward two adaptive algorithms for request selection and dispatch,both algorithms are based on feedback control and each of them has a unique request selection and dispatch strategy.The experiment result is also given.It shows that the model presented here is suitable for heterogeneous Web Server clusters,as the clusters can achieve better QoS performance when these two algorithms are applied.