A self-tuning client-side metadata prefetching scheme for wide area network file systems

作     者：Bing WEI Limin XIAO Yao SONG Guangjun QIN Jinbin ZHU Baicheng YAN Chaobo WANG Zhisheng HUO Bing WEI;Limin XIAO;Yao SONG;Guangjun QIN;Jinbin ZHU;Baicheng YAN;Chaobo WANG;Zhisheng HUO

作者机构：Laboratory of Software Development Environment Beihang University School of Computer Science and Engineering Beihang University Smart City College Beijing Union University 

出 版 物：《Science China(Information Sciences)》 (中国科学:信息科学(英文版))

年 卷 期：2022年第65卷第3期

页      面：78-94页

核心收录：

学科分类：12[管理学] 1201[管理学-管理科学与工程(可授管理学、工学学位)] 08[工学] 081201[工学-计算机系统结构] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by National key R&D Program of China (Grant No. 2018YFB0203901) National Natural Science Foundation of China (Grant No. 61772053) the Fund of the State Key Laboratory of Software Development Environment (Grant No. SKLSDE-2018ZX-10) Science Challenge Project (Grant No. TZ2016002) 

主　　题：wide area network file systems multiple workloads metadata prefetching correlation-directed prefetching directory-directed prefetching self-tuning prefetching 

摘      要：Client-side metadata prefetching is commonly used in wide area network(WAN) file systems because it can effectively hide network latency. However, most existing prefetching approaches do not meet the various prefetching requirements of multiple workloads. They are usually optimized for only one specific workload and have no or harmful effects on other workloads. In this paper, we present a new self-tuning client-side metadata prefetching scheme that uses two different prefetching strategies and dynamically adapts to workload changes. It uses a directory-directed prefetching strategy to prefetch the related file metadata in the same directory, and a correlation-directed prefetching strategy to prefetch the related file metadata accessed across directories. A novel self-tuning mechanism is proposed to efficiently convert the prefetching strategy between directory-directed and correlation-directed prefetching. Experimental results using real system traces show that the hit ratio of the client-side cache can be significantly improved by our self-tuning client-side prefetching. With regards to the multi-workload concurrency scenario, our approach improves the hit ratios for the no-prefetching, directory-directed prefetching, variant probability graph algorithm, variant apriori algorithm, and variant semantic distance algorithm by up to 15.22%, 6.32%, 10.08%, 11.65%, and10.73%, corresponding to 25.24%, 18.11%, 23.53%, 24.94%, and 24.19% reductions in the average access time, respectively.