Considering block popularity in disk cache replacement for enhancing hit ratio with solid state drive

The Solid State Drive (SSD) is now becoming a main stream in storage systems. It is widely deployed as cache for hard disk drive (HDD) to speed up the execution of data intensive applications. In this paper we propose a novel block replacement algorithm for flash-based disk cache, named Block Replacement based on Popularity(BRP). Using the frequency and recency of block access, it calculates the block popularity to select the block which will be evicted from SSD. This avoids cache pollution and keeps popular blocks in SSD cache, leading to high hit ratio. Meanwhile, the proposed scheme reduces block replacements, and thus incurs less write operations to SSD. As a result, BRP enhances the performance of storage and the lifetime of SSD. Computer simulation demonstrates that the proposed scheme consistently outperforms five existing cache replacement algorithms with two different kinds of traces.