高性能混合结构的瓦记录磁盘系统的设计与实现  

Design and implementation of a high performance hybrid shingled write disk system

作　　者：马留英[1,2] 肖文健[1,2] 董欢庆[1] 许鲁[1] 

机构地区：[1]中国科学院计算技术研究所,北京100190 [2]中国科学院大学,北京100049

出　　处：《高技术通讯》2017年第2期140-149,共10页Chinese High Technology Letters

基　　金：863计划(2013AA013205);中国科学院先导专项基金(XDA06010401);中国科学院重点部署基金(KGZD-EW-103-5(7))资助项目

摘　　要：对新的磁记录技术——瓦记录(SMR)进行了性能分析,针对SMR叠瓦式的磁道布局方式严重限制了其随机写性能,希捷公司的瓦记录磁盘(SSWD)在磁盘内部使用持久缓存虽能解决SMR叠瓦特性导致随机写访问受限,但其在持续随机写入的情景下性能表现很差的问题,设计了一种结合固态硬盘(SSD)的混合瓦记录磁盘(HSWD)结构;使用SSD作为持久缓存,实现了全相联和组相联两种持久缓存到本地存储的映射策略,以及三种持久缓存回收策略——LRU、FIFO和MOST,并通过试验和理论分析分别对比了两种映射策略和三种回收策略。最后,通过测试对比HSWD、SSWD和Flashcache的性能,结果表明,HSWD较SSWD和Flashcache在持续随机写性能上有了明显提升,例如在回放hm0的测试中,HSWD的性能较SSWD提升2.25倍,较Flashcache提升1.32倍。The shingled magnetic recording （SMR）, a new magnetic recording technique, was analyzed, and the follow- ing were pointed out ： the main drawback of the SMR is that random-write access to the disk is restricted due to the overlaps in the layout of data tracks ; The seagate shingled write disk （SSWD） mitigates the random-write access re- strictions by using an internal persistent cache, but it encounters the poor performance with sustained random writes. In consideration of the situation, a hybrid shingled write disk （HSWD） system was designed by combining it with the solid state drive （SSD）. Then, two different policies for caching between the persistent cache and the n- ative region, called the fully-associative and the set-associative）, as well as the three different collection policies of LRU, FIFO and MOST, were implemented, and they were compared respectively by some experiments and theoretical analysis. The performance of the HSWD was tested and compared with the SSWD and Flashcache. The evaluation re- sults demonstrated that the performance in persistent random writing of the HSWD was great higher then the SSWD and Flashcache, for example, 2.25x faster than the SSWD, and 1.32x faster than Flashcache in replaying hm0 trace.

关 键 词：瓦记录(SMR) 瓦记录磁盘(SSWD) 固态硬盘(SSD) 混合系统 缓存策略 回收策略 

分 类 号：TP333[自动化与计算机技术—计算机系统结构]