A Dynamic Load-Balancing Algorithm for Heterogeneous Web Server Cluster
Cheng Guo · Chinese Journal of Computers · 2005
As increasing the embedded objects and the database searching tasks in Web Pages, there is larger difference among the loads of different server in a cluster system, which becomes more difficult for a heterogeneous Web server cluster to achieve high performance. In this paper, the authors present a dynamic load balancing algorithm MDC(Multiplicative Decrease in Critical area). For each of the servers in the cluster, the algorithm can more accurately evaluate the current load state by using the Equivalent Load Alternant and can more efficiently restrain the occurring of the reject service phenomenon by using a special MDC operator. Besides, the authors apply a method of random distributing base probability to assign each request to an appropriate server in terms of their weight. All the parameters that will be used in the algorithm can be acquired by simulated test. The authors also provide improved approximation results of above algorithm for the case where documents consist of relatively many embedded objects or database searches and lots of requests arrived the dispatcher synchronously.