A Group-Based Buffer Management for SSD

Abstract

Random writes limit the application of SSDs significantly because of their poor latency and high garbage collection overhead. Traditional page-based and block-based buffer management algorithms cannot achieve both high buffer hit ratio and good destage sequentiality at the same time. In this paper, we propose a hybrid scheme called the group-based buffer management (GBBM). To improve buffer hit ratio and decrease write/erase counts, GBBM divides buffer space into Page Region and Group Region. The frequently accessed data pages are placed at the Page Region, while infrequently accessed random written data are grouped in the Group Region. GBBM has been evaluated extensively through simulations. The write counts of GBBM show an average decrease of 12.7% compared with page-level buffer scheme. Compared with hybrid buffer management such as CBM, GBBM decreases the average write/erase count by 14.3%/12.1%. The write hit ratio of GBBM shows a 4.5% improvement as compared with PAB. The proposed GBBM can significantly reduce the number of write operations while maintaining a relatively high buffer hit ratio.