A workload-based analysis of software aging, and rejuvenation

We present a hierarchical model for the analysis of proactive fault management in the presence of system resource leaks. At the low level of the model hierarchy is a degradation model in which we use a nonhomogeneous Markov chain to establish an explicit connection between resource leaks, and the failure rate. With the degradation model, we prove that the failure rate is asymptotically constant in the absence of resource leaks, and it is increasing as leaks occur & accumulate, which confirms the resource leaks as an aging source. The proactive fault management (PFM) is modeled at the higher level as a semi-Markov process. The PFM model takes as input the degradation analysis from the low-level model, and allows us to determine optimal rejuvenation schedules with respect to various system measures.