【摘要】 廉价冗余磁盘阵列(RAID)的可靠性是一个研究热点.当磁盘的失效率符合泊松同分布时,可以利用一般的可靠性理论来计算磁盘阵列的可靠性.然而,当磁盘的失效率分布不符合泊松同分布时,继续利用传统的可靠性评估理论来评估RAID的可靠性就显得不太合适.提出了一种基于蒙特卡洛随机仿真的可靠性仿真方法来评估RAID的可靠性.首先假设磁盘的失效率符合Weibull分布,分析了RAID阵列在整个生命周期中的不同状态;其次,采样不同状态转移间的概率,并且仿真RAID阵列的时序行为;最后,记录仿真过程中的可靠性评估指标.为了验证仿真方法,做了两个实验来比较磁盘失效率分别满足Weibull分布和泊松同分布时的可靠性指标.实验结果显示理论值和仿真值之间的偏差是2%.更多还原

【Abstract】 High reliability is essential for RAID,when the disk failure distribution doesn’t follow a homogeneous Poisson process,it is not appropriate to evaluate the RAID reliability with traditional reliability theory based on the assumption that the disk failure follow homogeneous Poisson process.How to evaluate the reliability of RAID? In this paper,we present a reliability evaluation method(Monte Carlo simulation) which is already used in other discipline.Firstly,we analyze the different state of RAID in its lifetime and assume that the disk failure follows Weibull distribution in the following experiment.Secondly,we sample the transition probability of different states and simulate the chronological behavior of RAID system.Finally,we record the reliability metrics in simulation process.In order to test the simulation algorithm,we do another experiment in which we compare the reliability of RAID in which the disk failure follows Weibull distribution with the reliability of RAID in which the disk failure follows homogeneous Poisson process.Experiment shows that the deviation between the theory value and the simulation value is less than 2%.It shows that our simulation algorithm is authoritative.更多还原