Estimation of service reliability and performance in grid environment

Service time for the tasks with a predefined deadline is an important parameter in the evaluation of a grid resource manager (GRMS). This parameter is affected directly by the failures of connection links and computational resources. In this paper, a new approach to estimate the reliability of a service and mathematical expectation of service time considering failure existence is proposed. In this approach unlike the current approaches which only consider permanent failures, both permanent and transient failures are considered. Also, in the previous works in order to increase the reliability and consequently to decrease the service time, the use of parallel resources was suggested. Nevertheless, due to the cost constraint the use of parallel resources is not practical. In this paper, the use of passive parallel systems to increase the reliability of grid services is suggested and the reliability and service time in the presence of passive parallel replica resources are analyzed. A passive parallel system has lower impact on reducing the service time, but it is more economical and consequently more applicable