An approximate mean value analysis approach for system management and overload control

Blocking is the phenomenon where a service request is momentarily stopped, but not lost, until the service becomes available again. Despite its importance, blocking is a difficult phenomenon to model analytically, because it creates strong inter-dependencies in the systems components. Mean Value Analysis (MVA) is one of the most appealing evaluation methodology since its low computational cost and easy of use. In this paper, an approximate MVA for Bloking After Service is presented that greatly outperforms previous results. The new algorithm is obtained by analyzing the inter-dependencies due to the blocking mechanism and by consequently modifying the MVA equations. The proposed algorithm is tested and then applied to a capacity planning and admission control study of a web server system