Availability Analysis of Software Systems with Rejuvenation and Checkpointing
Availability Analysis of Software Systems with Rejuvenation and Checkpointing
复制标题
DOI：
10.3390/math9080846
复制
发表时间：
2021-04
期刊：
影响因子：
2.4
通讯作者：
Junjun Zheng;H. Okamura;T. Dohi
中科院分区：
文献类型：
--
作者：
Junjun Zheng;H. Okamura;T. Dohi
在软件可靠性工程中，软件复壮和检查点技术被广泛用于提高系统可靠性和加强数据保护。本文提出了一个由复合随机Petri奖励网及其非马尔可夫可用性模型组成的随机框架来描述可操作软件系统的动态行为，其中基于时间的软件恢复和检查点都是非周期性进行的。特别是，除了可能导致系统故障的软件老化问题外，人为错误因素（即，系统操作员的误操作）。为了求解基于随机Petri网可达图的非马尔可夫可用性模型的平稳解，考虑了相扩展方法.该模型实际上不是半马尔可夫过程和马尔可夫再生过程等平凡随机模型.在数值实验中，我们说明了稳态系统的可用性，并找到最佳的软件复兴政策，最大限度地提高稳态系统的可用性。人为错误因素对稳态系统可用性和最佳软件复兴触发时间的影响也进行了评估。数值结果表明，检查点设置过程中的人为错误不仅降低了系统的可用性，而且对最优恢复触发时间产生了显著影响，因此在系统建模过程中不应忽视。
In software reliability engineering, software-rejuvenation and -checkpointing techniques are widely used for enhancing system reliability and strengthening data protection. In this paper, a stochastic framework composed of a composite stochastic Petri reward net and its resulting non-Markovian availability model is presented to capture the dynamic behavior of an operational software system in which time-based software rejuvenation and checkpointing are both aperiodically conducted. In particular, apart from the software-aging problem that may cause the system to fail, human-error factors (i.e., a system operator’s misoperations) during checkpointing are also considered. To solve the stationary solution of the non-Markovian availability model, which is derived on the basis of the reachability graph of stochastic Petri reward nets and is actually not one of the trivial stochastic models such as the semi-Markov process and the Markov regenerative process, the phase-expansion approach is considered. In numerical experiments, we illustrate steady-state system availability and find optimal software-rejuvenation policies that maximize steady-state system availability. The effects of human-error factors on both steady-state system availability and the optimal software-rejuvenation trigger timing are also evaluated. Numerical results showed that human errors during checkpointing both decreased system availability and brought a significant effect on the optimal rejuvenation-trigger timing, so that it should not be overlooked during system modeling.