Refined non-homogeneous Markovian models for a single-server type of software system with rejuvenation

Long running software systems are known to experience an aging phenomenon called software ageing, 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 a proactive 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. In this paper, we reconsider the non-homogeneous Markovian models for a single-server type of software system with rejuvenation in Garg et al., and revisit them from the theoretical viewpoint. More precisely. it is assumed in these models that software failures can occur with positive probability during idle periods in transactions systems, but we exclude this unreasonable situation in our refined models.