The Efficient Circular Flash Memory Cache Mechanism For Reducing Energy Consumption of Disks

Abstract

Recently, flash memory in serving as a cache layer for disks has gained a lot of attention. However, the out-place update characteristics of flash memory leads to an increase in garbage collection overhead and a decrease in the cache hit ratio. This paper proposes a management scheme for a circular cache taking into consideration the characteristics of flash memory, and examines new data, block replacement and a garbage collection mechanism. We evaluated the proposed scheme using a trace-driven simulator. The proposed scheme can save disk energy about 9 similar to 15%, compared with a system without using flash memory caches, or about 1 similar to 2%, compared with a typical system using flash memory caches. Moreover, It also provides the average response time about 0.5 similar to 1ms faster than the existing system.