Effect of Maintenance on the Dependability and Performance of Mulitprocessor Systems

This paper presents analytic models for dependability and performance evaluation of multiprocessor systems with both on-line and off-line maintenance. Markov models are developed to compute the system reliability and performance availability incorporating the reliability of the maintenance processor. The maintenance processor failure is considered separately in order to emphasize its effect on system performance and dependability. The reliability of the maintenance processor can not be ignored for degradable multiprocessors. Probabilistic models are presented to compute the system downtime and the service cost for three off-line maintenance policies: scheduled maintenance (SM), unscheduled maintenance (UM), and scheduled & unscheduled maintenance (SUM). The SUM policy, that combines both SM and UM, can be used to give a compromise between cost and downtime.