Realistic Simulation of Large Scale Distributed Systems using Monitoring

In this paper we present an extension to MONARC, a generic simulator for large scale distributed systems, which allows realistic evaluation of various actual distributed system technologies based on real-world monitored data supplied by MonALISA. The field of modelling and simulation was long-time seen as a viable solution to develop new algorithms and technologies and to enable the development of large-scale distributed systems, where analytical validations are prohibited by the nature of the encountered problems. This paper presents a novel approach to combining two distributed systems domains, monitoring and simulation, highlighting a realistic solution to the problem of accurately evaluating various distributed systems technologies using simulation. We also present a simulation study which demonstrates the interoperability between the simulation framework and the monitoring instrument, demonstrating important properties of the US LHCNet research network in the context of the LHC experiments in CERN.