Reliability, in terms of Grid component fault tolerance and minimum quality of service, is an important aspect that has to be addressed to foster Grid technology adoption. Software reliability is critically important in today's integrated and distributed systems, as is often the weak link in system performance. In general, reliability is difficult to measure, and specially in Grid environments, where evaluation methodologies are novel and controversial matters. This paper describes a straightforward procedure to analyze the reliability of computational grids from the viewpoint of an end user. The procedure is illustrated in the evaluation of a research Grid infrastructure based on Globus basic services and the GridWay meta-scheduler. The GridWay support for fault tolerance is also demonstrated in a production-level environment. Results show that GridWay is a reliable workload management tool for dynamic and faulty Grid environments. Transparently to the end user, GridWay is able to detect and recover from any of the Grid element failure, outage and saturation conditions specified by the reliability analysis procedure.
['Eduardo Huedo', 'Rubén S. Montero', 'Ignacio Martín Llorente']
Evaluating the reliability of computational grids from the end user's point of view