Optimal software rejuvenation for tolerating soft failures

Andras Pfening, Sachin Garg, Antonio Puliafito, Miklos Telek, Kishor S. Trivedi

Research output: Contribution to journalConference article

76 Citations (Scopus)


In recent studies, the phenomenon of software `aging' has come to light which causes performance of a software to degrade with time. Software rejuvenation is a fault tolerance technique which counteracts aging. In this paper, we address the problem of determining the optimal time to rejuvenate a server type software which experiences `soft failures' (witnessed in telecommunication systems) because of aging. The service rate of the software gradually decreases with time and settles to a very low value. Since the performability in this state is unacceptable, it is necessary to `renew' the software to its peak performance level. We develop Markov decision models for such a system for two different queuing policies. For each policy, we define the look-ahead-n cost functions and prove results on the convergence of these functions to the optimal minimal cost function. We also prove simple rules to determine optimal times to rejuvenate for a realistic cost criterion. Finally, the results are illustrated numerically and the effectiveness of the MDP model is compared with that of the simple rules.

Original languageEnglish
Pages (from-to)491-506
Number of pages16
JournalPerformance Evaluation
Publication statusPublished - Oct 1 1996
EventProceedings of the 1996 18th International Symposium on Performance Evaluation - Lausanne, Switz
Duration: Oct 7 1996Oct 12 1996

ASJC Scopus subject areas

  • Software
  • Modelling and Simulation
  • Hardware and Architecture
  • Computer Networks and Communications

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