Load balancing in distributed Web server systems with partial document replication

Abstract

How documents of Web site are replicated and where they are placed among the server nodes have an important bearing on balance of load in a Distributed Web Server (DWS) system. The traffic generated due to movements of documents at runtime during load balance could also affect the performance of the DWS system. In this paper, we prove that minimizing such traffic in a DWS system is NP-hard. We propose several heuristic document distribution schemes that perform partial replication of a site's documents at selected server locations so that load balancing is maintained. We carry out simulation of these schemes using both a synthetic workload and real log data. From the simulation results, we find that using an additional 50% of storage for replication, our heuristics can improve the load balancing performance in the DWS system by 48%, and the internal traffic due to movements of documents has an negligible effect on the system's performance.

Review of SDN-based load-balancing methods, issues, challenges, and roadmap

“…Static server LB techniques include round-robin, IP hashing, and least connection, while dynamic server LB techniques include weighted round-robin, least traffic, and adaptive load balancing [42].…”