RAID10L: A high performance RAID10 storage architecture based on logging technique

Abstract

RAID10 storage system suffers the relatively poor write performance due to the write request must be served by both disks in a mirror set. To address this problem, in this paper we propose a novel RAID10 storage architecture, called RAID10L, which extends the data mirroring redundancy of RAID10 by incorporating a dedicated log disk. The goal of RAID10L is to significantly improve the write performance of RAID10 at some little expense of reliability. In RAID10L both read and write requests are processed in a balance scheme. For every write request, RAID10L keeps two copies of the write data: one in its normal place of data disk chosen by a write balance scheme and the other in the log disk by writing sequentially. The update to another data disk in a mirror set is delayed to the next quiet period between bursts of client activity. Reliability analysis shows that the reliability of RAID10L, in terms of MTTDL (mean time to data loss), is somewhat worse than RAID10 but much better than RAID5. On the other hand, our prototype implementation of RAID10L driven by Iometer benchmark shows that RAID10L outperforms RAID10 by up to 47.1% and RAID0 by 27.3% in terms of average response time. Driven by some real-life traces, RAID10L gains improvement up to 30.7% with an average of 27.7% than RAID10 in terms of average response time.