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 following 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 restrictions 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 native 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 results 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.
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