Flash 메모리 저장장치의 신뢰성 향상을 위한 데이터 관리 기법의 설계 및 구현

Abstract

Since flash memory has many attractive characteristics such as high performance, non-volatility, low power consumption and shock resistance, it has been widely used as a storage media in embedded and computer system environments. However, there are many shortcomings in flash memory such as potentially high I/O latency due to erase-before-write and poor durability due to limited erase cycles. To address these performance and reliability anomalies, many large-scale storage systems use redundancy-based parallel access schemes such as RAID techniques. However, such redundancy-based schemes incur high overhead due to generating and storing redundancy information, especially in flash-based storage systems. In this paper, we propose a novel and performance-effective approach using a redundancy-based data management scheme in flash storage, called Flash-aware Redundancy Array. The proposed technique not only reduces the redundancy management overhead by performing redundancy update operations during idle periods, but also provides a preventive mechanism to recover data from unexpected read errors occurring before such redundancy update operations finish. From the experiments, we found that the proposed technique improves flash-based storage systems by 19% in average execution time as compared to other redundancy-based approaches.