Analysis of a two-level software rejuvenation policy

A two-level rejuvenation policy for software systems with degradation process is studied. Both full restarts and partial restarts are considered in this rejuvenation strategy. A semi-Markov process model is constructed, and based on its closed-form solution we obtain the system availability as a bivariate function. Then, the rejuvenation policy is analyzed to maximize the system availability. Several different scenarios of software rejuvenation strategy are demonstrated by numerical examples.