共模失效情况下集群系统可用性分析

Availability analysis of cluster systems in the case of common mode failure

针对存在共模失效情况下的集群系统,基于马尔科夫过程分析方法,分析了单集群节点构成系统的可用性.在此基础上分别建立了由2个集群节点组成的系统在无CMF(共模失效)和有CMF情况下的连续时间马尔科夫链(CTMC)模型,然后通过求解相应的线性方程组,对模型在稳定状态下可用性的数值进行比较和分析,得出了2种不同情况下集群系统可用性的优劣比较结论,采用随机回报网(SRN)仿真工具和SPNP 6.0辅助求解工具进行了验证,仿真结果与CTMC的理论分析结果相符合,为进一步研究异构集群系统的可用性奠定了基础.

Availability analysis of cluster systems in the case of CMF（common mode failure） was carried out by Markov process.Firstly,the availability of system with one cluster node was analyzed.Then on the basis of the analysis,the system consisting of two cluster nodes,the two CTMC（continuous time Markov chain） models in the case of no CMF and in the case of with CMF were constructed respectively.Moreover,numerical comparison of steady availability for these two cases was conducted by solving related linear equations and the conclusion on the priority and inferiority comparison of different cases was derived thereby.Furthermore,its correctness was simulated and validated by SRN（stochastic reward nets） and SPNP（stochastic Petri nets package） 6.0 software.The simulation result are well consistent with the CTMC-based theoretical one,which offers foundations for further investigating availability of heterogeneous cluster systems.