Study And Design Of Screen Web Server Cluster

Web is changing from a content distribution mechanism to a service platform. A large number of services and applications are carried out on Web.The rapid development of Web brings enormous challenges to network transmission and server processing. Compared to the development of network transmission quality, the load bottleneck of the Web-server is particularly prominent. Academia and industry at home and abroad have been in researching on web server application software, operating systems, middleware and server clusters. The cluster technology has become an effective solution of server overload and providing high-performance server. The research based on the third and the forth layers of the OSI reference model has been more mature. At present, the Web load balancing based on the content exchange of the seventh layers is hot and difficult.Through reading literature available, the paper finished some basic theoretical knowledge of the Web sites that were constructed by cluster technology. It also researched and analyzed in-depth the load balancing cluster technology and content exchange technology. Then further researches and analysis of web cluster solution based on content exchange were done. Some inadequacies of traditional solutions were found, such as the lack of background transparency, poor system scalability and lower processing efficiency. The paper analyzed the work principle of various request routing mechanisms and the advantages and disadvantages of their solutions, focusing on the completion of the processing problems of connection in TCP adhesion. A new Web cluster system named Screen-Web server clustering architecture was given after the comparative analysis of the research in past. The paper described the data flow processing of the cluster system, designed the four important core modules and given the core processing algorithms of them.The cluster architecture of Screen Web server adopts classification granular request load distribution mechanism. The accept control module and connection module in the front of the request distributor give full play to the higher efficiency of low-layers load balancing and provide control of distinction between priorities for Web request. The TCP glue module establishes two connections as "bridging role" between clients and real servers. The packet analysis module and request scheduling module in the front of the real Web Server analyze HTTP protocol. They chose Server and forward request according to the content of user's real requests. Then more advantages of Content-aware request distribution were provided. With Linux Netfilter under the framework of the network packet processing power, paper has realized the core features of the screen Web server cluster architecture.The results of experiments show that the time of Web request response is less obviously than the traditional single-server and the forth layer exchange Web server cluster when the architecture is in the high request load circumstances.