A two-pass web document allocation method for load balancing in the multiple grouping of a Web cluster system

For a practical operation, multiple groups of Web servers with different performance may coexist in a Web cluster. In this paper, we propose a quantitative method based on a typical M/G/1 queuing model to analyze and equalize the service performance of multiple groups of Web servers. We also propose a two-pass method for providing uniform distribution of Web documents to the multiple grouping of a Web cluster system. In addition to the primary function of maintaining a load balance of Web requests, we introduce the extra pass to distribute the complement parts of the Web documents to the disks of the other servers. Usually, these hidden documents are not used for normal operation. If one of the servers is down, these servers can be replaced by the spare server that has the spare copy of the Web documents by the allocation of the second pass.