一种容三盘失效纠删码的单数据盘失效快速重建方法  

EDS:A Novel Scheme for Boosting Single-Disk Failure Recovery of Triple-Erasure-Correcting Code Storage Systems

作　　者：邱丽娜[1] 王芳[2] 李楚[3] 

机构地区：[1]华中科技大学计算机学院,武汉430074 [2]武汉光电国家实验室,武汉430074 [3]教育部信息存储及应用实验室,武汉430074

出　　处：《计算机学报》2013年第10期2041-2052,共12页Chinese Journal of Computers

基　　金：国家"九七三"重点基础研究发展规划项目基金(2011CB302301);国家"八六三"高技术研究发展计划项目基金(2013AA013203);国家自然科学基金(61025008;60933002;61232004)资助~~

摘　　要：现代存储系统采用纠删码避免因磁盘故障导致的数据丢失，提高系统的可靠性和可用性.因容三盘失效纠删码，如TP编码和STAR编码，可同时容忍系统中任意3个磁盘损坏，可靠性超过RAID6编码，故而受到越来越多的关注.针对发生频率最高的单盘故障实现快速重建恢复数据服务，尚未得到有效实现.重建方案有多种，选择何种重建方案会影响重建性能甚至影响前端服务的响应时间.传统的单盘重建方法不仅耗时良久而且会造成带宽的浪费.针对单盘重建中传统方法的缺点，提出一种均分机制方法，利用处于“均分状态”的重建校验集合推理出单盘重建时所使用的数据量的最优解从而找出最佳重建方案，减少磁盘I/O时间，以加速重建过程.测试结果表明与传统方法相比，均分机制方法减少TP编码25%～30.6%和STAR编码30%～33.64%的磁盘读数据量，使重建时间显著减少；且在不同的数据块和不同的磁盘个数时，均分机制方法的重建性能均优于传统方法.Modern storage systems apply erasure codes to protect against disk failures and improve system reliability and availability. MDS codes such as STAR code, Triple Parity （TP） have attracted to more and more attention because they are triple-erasure-correcting and offering higher reliability than RAID6 codes. It has not been solved effectively yet about how to complete fast recovery from single failure in systems using triple-erasure-correcting codes. There exist many recovery solutions and it makes great influence on recovery performance and response time of requests from foreground. Conventional scheme of recovering system from single failure is time consuming and bandwidth wasting. To address this problem, we propose an Equal Division Scheme （EDS） for triple-erasure-correcting codes to realize fast single failure recovery. Our scheme deduced the amount of data transmitted for single failure recovery through using recovery parity collection in Equal Division Status and then found out an optimal recovery collection to reduce disk I/O time so that recovery process is boosted. Experiment results show that EDS consumes 25%-30.6% less data transmission approximately for TP and 30%-33.64% less for STAR than the conventional strategy and reduces recovery time observably. And with different chuck sizes and different disk numbers, EDS outperforms conventional remarkably.

关 键 词：磁盘阵列 可靠性 磁盘损坏 重建算法 

分 类 号：TP302[自动化与计算机技术—计算机系统结构]