Semi-Markov Modeling Approach for Deteriorating Systems with Preventive Maintenance

Software systems experience gradual performance degradation despite of which they are required to perform service, though at a degraded level. Different preventive and corrective techniques (restart, rejuvenation etc. ) have been applied to restore efficient service of the system. In this paper, we model the process of degradation together with the corrective actions of minimal repair, major repair and restart technique via a semi-Markov process. In addition, at the lower level, we propose a performance model to study the impact of load on degradation, using Markov reward models. Closed-form solution for the dependability of the system in terms of availability, reliability and maintainability are obtained. The proposed model is also compared with an existing model. The analysis conducted, using numerical results, indicates the efficiency of our approach.