| Summary: | 碩士 === 國立中興大學 === 資訊科學與工程學系所 === 107 === In today''s computer systems, the multi-tiered storage architecture, which consist of mechanical hard drive disks (HDDs) and solid-state hard disks (SSDs), utilizes SSDs as the cache of HDDs. Thus, the multi-tiered storage architecture enjoys the advantages of SSDs’ high access speeds and low power consumption and HDD’s large capacity and thus make users to have a better experience in terms of I/O performance. However, under the multi-tiered storage architecture, we have observed the following four problems: (1) Metadata duplication, (2) Double caching, (3) Blind page cache management, and (4) Delayed/inaccurate SSD information.
This thesis addresses this four problems and proposes the corresponding solutions. First, we develop an integrated data structure that integrates the metadata nodes maintained by both the page cache and SSD cache managers. Second, Lazy caching mechanism is designed to decrease the number of double caching data. Third, the page cache is divided into Image and Image regions, and different cache management strategies are used to manage the data in these two regions. Finally, a new SSD cache data algorithm is proposed to make the metadata information maintained in the SSD cache manager more accurate. From the experimental results, the solutions proposed in this thesis can indeed reduce the number of metadata nodes maintained by the page cache and SSD cache manager, decrease the data that are simultaneously cached in the page cache and SSD cache, and successfully reduce the average I/O response time.
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