AMC: an adaptive multi-level cache algorithm in hybrid storage systems

摘要

Hybrid storage systems that consist of flash-based solid state drives (SSDs) and traditional disks are nowrnwidely used. In hybrid storage systems, there exists a two-level cache hierarchy that regard dynamic randomrnaccess memory (DRAM) as the first level cache and SSD as the second level cache for disk storage. However,rnthis two-level cache hierarchy typically uses independent cache replacement policies for each level,rnwhich makes cache resource management inefficient and reduces system performance. In this paper, we proposerna novel adaptive multi-level cache (AMC) replacement algorithm in hybrid storage systems. The AMCrnalgorithm adaptively adjusts cache blocks between DRAM and SSD cache levels using an integrated solution.rnAMC uses combined selective promote and demote operations to dynamically determine the level inrnwhich the blocks are to be cached. In this manner, the AMC algorithm achieves multi-level cache exclusivenessrnand makes cache resource management more efficient. By using real-life storage traces, our evaluationrnshows the proposed algorithm improves hybrid multi-level cache performance and also increases the SSDrnlifetime compared with traditional multi-level cache replacement algorithms.