HotR: Alleviating Read/Write Interference with Hot Read Data Replication for Flash Storage
Suzhen Wu1, Weiwei Zhang1, Bo Mao2 and Hong Jiang3
1Computer Science Department of Xiamen University, Xiamen, Fujian, China
2Software School of Xiamen University, Xiamen, Fujian, China
maobo@xmu.edu.cn
3Department of Computer Science & Engineering at the University of Texas-Arlington, USA
ABSTRACT
The read/write interference problem of flash storage remains a critical concern under workloads with a mixture of read and write requests. To significantly improve the read performance in face of read/write interference, we propose a Hot Data Replication scheme for flash storage, called HotR. HotR utilizes the asymmetric read and write performance characteristics of flash-based SSDs and outsources the popular read data to a surrogate space such as a dedicated spare flash chip or an overprovisioned space within an SSD. By servicing some conflicted read requests on the surrogate flash space, HotR can alleviate, if not entirely eliminate, the contention between the read requests and the on-going write requests. The evaluation results show that HotR improves the state-of-the-art scheme in the system performance and cost efficiency significantly. Consequently, the tail-latency of the flash-based storage systems is also reduced.
Keywords: Flash Storage, Read/Write Interference, Hot Read Data Replication, Performance Evaluation.
