Research On Fine-grained Software Rejuvenation Policy And Related Techniques

Computer system becomes more and more complex, and many software bugs inducing software aging cannot be avoided, which has been a fact that we have to accept and face up to. In order to reduce the loss that results from the performance degradation and failure of computer system as possible, software rejuvenation should be researched. The background, actuality and problems of software rejuvenation are investigated in this paper. And then four aspects are studied, including novel single-level software rejuvenation policies, multi-level software rejuvenation policy, fine-grained restart technique and the model of multi-level software rejuvenation policy. The main contributions of this dissertation are summarized as foltows:Firstly, two kinds of novel single-level policies, time & detection-based software rejuvenation policy and given-failure-probability-based software rejuvenation policy, are proposed. The system availability and the rejuvenation cost of the two novel policies are analyzed using semi-Markov process, and the results demonstrate that they sometimes can further decrease downtime, reduce rejuvenation coat and improve system reliability. These basic researches have satisfied the requirements, perfected the class of policy, and provided necessary support for fine-grained software rejuvenation.Secondly, the idea that constitutes multi-level software rejuvenation policy according to the rule of performance degradation is put forward, which aim at increase rejuvenation granularity. In this paper, the usage of system resource is inspected and the sampling data are treated with wavelet technique. Based on the treated results, the evaluated index of system performance and the rule of performance degradation are confirmed. Finally, the rejuvenation granularity is determined, the restart chain is formed, and the nested restart relations of all levels of restart object are illuminated.Thirdly, in order to ensure the safe restart of restart objects, fine-grained restart technique is researched. According to the related theories of software engineering, software architecture and data access relation between modules are analyzed, and then it is formalized. The restart dependence between modules is obtained by searching accessible path, on which the restart group of any module is defined and the restart...