評估快取與預先提取在儲存伺服器上的效能

Abstract

快取 (Caching) 與預先提取 (Prefetching) 對於儲存伺服器的運作是很重要的技術。由於記憶體與硬碟存取速度的差距持續增大，快取與預先提取對系統效能的提升在現代的儲存伺服器中扮演相當重要的角色。在這篇論文中，我們在廣達公司 (Quanta Computer Incorporation) 製作的，內部代號為RF2的儲存伺服器上，針對原有的快取機制的效能進行分析，提出新的快速快取 (Fast Caching) 的設計來降低其純取時間以及儲存伺服器處理機的工作量，同時我們也加入新的適應性預先提取技術 (Adaptive Prefetch) 進一步去縮短讀取磁碟的時間。我們利用trace-driven simulation 的方式實驗並且預估我們所提出的快速快取與適應性預先提取技術在RF2儲存伺服器上的效能表現。我們發現，我們所提出的技術對於TPC-C的效能相當大的改善。

Caching and prefetch are important techniques for designing a storage system. As the speed gap between memory and disk is so large today, caching and prefetch are critical to enterprise-class storage applications, which demands high-performance. In this thesis, we studied the performance of the latest mid-range storage server produced by Quanta Computer Incorporation (codename: Rb2). We analyzed the existing caching mechanism in the server and developed a fast caching methodology to reduce the cache access latency and processing overhead of the storage controller. In addition, we proposed a new adaptive prefetch scheme reduces the average disk access time seen by the host. Via trace-driven simulation, we evaluated the performance of our new caching and adaptive prefetch schemes. Our results showed the performance improvement for the TPC-C benchmark.