Dependability analysis of a client/server software system with rejuvenation

Long running software systems are known to experience an aging phenomenon called software aging, one in which the accumulation of errors during the execution of software leads to performance degradation and eventually results in failure. To counteract this phenomenon an active fault management approach, called software rejuvenation, is particularly useful. It essentially involves gracefully terminating an application or a system and restarting it in a clean internal state. We deal with dependability analysis of a client/server software system with rejuvenation. Three dependability measures in the server process, steady-state availability, loss probability of requests and mean response time on tasks, are derived from the well-known hidden Markovian analysis under the time-based software rejuvenation scheme. In numerical examples, we investigate the sensitivity of some model parameters to the dependability measures.