Reliable SSD based Hybrid-RAID System for Enhancing I/O Performance

초록

SSD consists of parallel NAND flash memory and has much strength in terms of power consumption, heat and noise compared to a hard disk drive(HDD). Its I/O performance is higher than that of HDD. However, the implementation of a SSD-based RAID system may reduce lifespan and lower the reliability of SSDs due to frequent updates of parity. Therefore, this paper proposes the block I/O management scheme in a Hybrid-RAID system, using the MLC and SLC types of SSD to improve the reliability and performance of a SSD based RAID. The proposed method stores data in a MLC disk and parity into a SLC disk. It implements erasure code at the device driver level to enhance encoding and decoding performance of a RAID-6 system. Experimental results reveal that encoding performance using proposed SSD based hybrid RAID-6 is improved from 7.4% up to 15%. However,decoding performance of the proposed MLC+SLC type, in a hybrid RAID-6 system, is 7.4%, 43.2%,38.3% faster than those of MLC+MLC, MLC-HDD in RAID-6 system and HDPA in RAID-4 system, respectively.