Scalable QoS Content-Aware Load Balancing Algorithm for a Web Switch Based on Classical Policies

This paper presents a load balancing solution for a cluster of Web servers that considers QoS in order to differentiate the service provided to the clients when the Web system is receiving a high volume of traffic. Adaptability is a needed feature to suit the balancing parameters to the fluctuations of the Web traffic. We monitor the incoming workload to the system and tune the parameters more frequently when the bursty arrivals trend increases. Throughput prediction enables to estimate the maximum utilization allowed in the servers for each service, and then to set a maximum number of accepted requests to set a limit in the utilization of the servers and to avoid a possible congestion situation, while guaranteeing the QoS. Classical dispatching policies are introduced and compared to analyse the behaviour of the algorithm. HTTP static and dynamic requests are considered in the workload.