The software rejuvenation is one of the most effective preventive maintenan
ce technique for operational software systems with high assurance requireme
nt. In this paper, we propose the workload-based software rejuvenation sche
me for a server type of software system, and develop stochastic models to d
etermine the optimal software rejuvenation schedules for some dependability
measures. In numerical examples, we evaluate quantitatively the performanc
e of workload-based software rejuvenation scheme and compare it with the ti
me-based rejuvenation scheme.