Block Replacement Scheme based on Reuse Interval for Hybrid SSD System

Abstract

Due to the advantages of fast read/write operation and low power consumption, SSD(Solid State Drive) is now widely adopted as storage device of smart phone, laptop computer, server, etc. However, the shortcomings of SSD such as limited number of write operations and asymmetric read/write operation lead to the problem of shortened life span of SSD. Therefore, the block replacement policy of SSD used as cache for HDD is very important. The existing solutions for improving the lifespan of SSD including the LARC scheme typically employ the LRU algorithm to manage the SSD blocks, which may increase the miss rate in SSD due to the replacement of frequently used block instead of rarely used block. In this paper we propose a novel block replacement scheme which considers the block reuse interval to effectively handle various data read/write patterns. The proposed scheme replaces the block in SSD based on the recency decided by reuse interval and age along with hit ratio. Computer simulation using workload trace files reveals that the proposed scheme consistently improves the performance and lifespan of SSD by increasing the hit ratio and decreasing the number of write operations compared to the existing schemes including LARC.

Priority-Based Hybrid File Storage Management System Using Logical Volume Manager

“…. 하이 브리드 저장장치 관련 연구들이 초점을 맞추고 있는 것 은 (1) SSD의 빠른 속도는 HDD의 느린 속도를, HDD 의 많은 용량은 SSD의 적은 용량을 서로 보완하는 활 용법 [8] 과, (2) 기계기반인 HDD의 반영구적 수명과 다르 게 플래시 메모리 기반인 SSD는 비교적 짧은 수명을 가진 점 [9] 이다.…”