人为错误对存储系统数据不可用和数据丢失的影响建模
Modeling Impact of Human Errors on the Data Unavailability and Data Loss of Storage Systems
摘要：
数据存储系统及其可用性在当代数据中心中起着至关重要的作用。尽管使用了自动故障转移等机制，但人类代理的作用及其破坏性错误是不可避免的。由于大量的磁盘驱动器用于exascale存储中心和他们的高故障率，在存储系统中的磁盘子系统已成为数据不可用（DU）和数据丢失（DL）的主要来源发起的人为错误。在本文中，我们研究的影响不正确的磁盘更换服务（IDRS）的数据存储系统的可用性和可靠性。为此，我们分析了IDRS在磁盘阵列中的后果，并进行蒙特卡罗模拟，以评估DU和DL在任务时间。所提出的建模框架可以处理a）不同的存储阵列配置和b）数据对象可生存性（DOS），表示系统级冗余（例如远程备份和镜像）的影响。在所提出的框架中，模型参数是从工业和科学报告中获得的，同时也是从一个有70个存储机架的数据中心中提取的现场数据。结果表明，忽略IDRS的影响，导致不可用性低估高达三个数量级。此外，我们的研究表明，通过考虑人为错误的影响，传统的信念的可靠性不同的独立冗余阵列（RAID）机制应予以修订。结果表明，在存在人为错误的情况下，与RAID5相比，RAID1可能导致较低的可用性。结果还表明，采用自动故障转移策略（使用热备盘）可以将人为错误的严重影响降低两个数量级。
英文摘要：
Data storage systems and their availability play a crucial role in contemporary datacenters. Despite using mechanisms such as automatic fail-over in datacenters, the role of human agents and consequently their destructive errors is inevitable. Due to very large number of disk drives used in exascale datacenters and their high failure rates, the disk subsystem in storage systems has become a major source of Data Unavailability (DU) and Data Loss (DL) initiated by human errors. In this paper, we investigate the effect of Incorrect Disk Replacement Service (IDRS) on the availability and reliability of data storage systems. To this end, we analyze the consequences of IDRS in a disk array, and conduct Monte Carlo simulations to evaluate DU and DL during mission time. The proposed modeling framework can cope with a) different storage array configurations and b) Data Object Survivability (DOS), representing the effect of system level redundancies such as remote backups and mirrors. In the proposed framework, the model parameters are obtained from industrial and scientific reports alongside field data which have been extracted from a datacenter operating with 70 storage racks. The results show that ignoring the impact of IDRS leads to unavailability underestimation by up to three orders of magnitude. Moreover, our study suggests that by considering the effect of human errors, the conventional beliefs about the dependability of different Redundant Array of Independent Disks (RAID) mechanisms should be revised. The results show that RAID1 can result in lower availability compared to RAID5 in the presence of human errors. The results also show that employing automatic fail-over policy (using hot spare disks) can reduce the drastic impacts of human errors by two orders of magnitude.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
