S-RAID中基于连续数据特征的写优化策略  

Write Optimization Strategy in S-RAID Based on Sequential Data Characteristics

作　　者：刘靖宇[1,2] 谭毓安[1,3] 薛静锋[1] 马忠梅[1] 李元章[1] 张全新[1] 

机构地区：[1]北京理工大学计算机科学与技术学院,北京100081 [2]河北工业大学计算机科学与软件学院,天津300401 [3]北京理工大学北京市海量语言信息处理与云计算应用工程技术中心,北京100081

出　　处：《计算机学报》2014年第3期721-734,共14页Chinese Journal of Computers

基　　金：国家"八六三"高技术研究发展计划项目基金(2013AA01A212);国家自然科学基金(61370063)资助~~

摘　　要：节能型磁盘阵列S-RAID通过对磁盘分组,关闭部分磁盘,降低存储系统部分性能来实现节能.为避免启动已关闭磁盘而产生额外能耗,S-RAID中的写操作全部采用"读-改-写"方式,影响了S-RAID的写性能.本研究提出一种S-RAID的优化结构:LS-RAID,在不提高存储系统能耗的条件下,优化S-RAID的写性能.LS-RAID适用于以连续访问为主的应用,通过磁盘分区,分离存储系统中的随机访问和顺序访问,降低了随机访问对存储系统性能的影响;提出一种数据增量校验算法,避免了写过程中对数据盘旧数据的读操作,降低了因"读-改-写"导致的写惩罚.实验表明,与S-RAID相比,在不增加系统能耗的情况下,LS-RAID的写速率可以提升至少56%.在提供相同写性能的条件下,LS-RAID可以关闭更多磁盘,进一步降低了存储系统能耗,提升了节能效果.S-RAID, a power-aware RAID, saves energy by grouping disks in the array and shut ting down most of them. In order to avoid spinning up disks that are put into standby mode, all write operations are read-modify-write in S-RAID, and that degrades its write performance. A new data layout based on S-RAID. LS-RAID, is proposed in this paper in order to optimize the write performance of the storage system with the same power consumption. LS-RAID is suitable for sequential data storage. Each disk in LS-RAID is divided into two parts. Random I/O is kept separate from sequential I/O. That can reduce the negative impact on the storage system caused by sequential I/O. The parity calculates with a new algorithm. Data Incremental Parity algorithm （DIP）. DIP calculates the parity only with the blocks that be written instead of all of them. The old data need not be read while the new data is written. That degraded write penalty caused by read-modify-write. Experiment shows that write performance of LS-RAID increased at least 56 % than S-RAID, and that makes it possible for LS-RAID to save more energy with the fixed data transfer rate.

关 键 词：连续数据存储 节能 写优化 磁盘阵列 校验 绿色计算中图法 

分 类 号：TP333[自动化与计算机技术—计算机系统结构]