An Intelligence Layer-7 Switch for Web Server Clusters
Saeed Sharifian, Mohammad Kazem Akbari, Seyed Ahmad Motamedi · 2005
In this paper we propose a new scheduling policy namely IRD (Intelligence Request Dispatcher) for web switches operating at layer-7 of OSI protocol stack in a web server farm .we classify dynamic and static requests. A hybrid Neuro-Fuzzy and LARD like approach is used to make route decision of dynamic and static requests separately. IRD select server with lower response time in an adaptive dispatching policy. In particular, we used the ANFIS (Adaptive Neuro Fuzzy Inference System) methodology to build a Sugeno fuzzy model to assigns each incoming dynamic request to the server with the least expected respon se time. This estimation is based on expected impact of each client's individual request on server's resources. this resources are , number of connection, CPU and disk usage .This parameters used to evaluate a load-weight of each serv er in a fuzzy manner and retrieved through feed-back. For Static requests an algorithm used to improve the cache hit ra te in Web cluster nodes according to their load-weights. It's goal is to improve load sharing in web clusters with dynamic and static information. A prototype implementation results confirm that proposed algorithm is more effective than representative request distribution algorithms, specially for dynamic requests that requires sophisticated policy and more service time than static information.