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Mobile Information Systems
Volume 2017, Article ID 1360413, 12 pages
https://doi.org/10.1155/2017/1360413
Research Article

RAID-6Plus: A Comprised Methodology for Extending RAID-6 Codes

State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, China

Correspondence should be addressed to Ming-Zhu Deng; moc.621@tdun_kd

Received 23 September 2016; Revised 26 December 2016; Accepted 10 January 2017; Published 23 February 2017

Academic Editor: Laurence T. Yang

Copyright © 2017 Ming-Zhu Deng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Existing RAID-6 code extensions assume that failures are independent and instantaneous, overlooking the underlying mechanism of multifailure occurrences. Also, the effect of reconstruction window is ignored. Additionally, these coding extensions have not been adapted to occurrence patterns of failure in real-world applications. As a result, the third parity drive is set to handle the triple-failure scenario; however, the lower level failure situations have been left unattended. Therefore, a new methodology of extending RAID-6 codes named RAID-6Plus with better compromise has been studied in this paper. RAID-6Plus (Deng et al., 2015) employs short combinations which can greatly reuse overlapped elements during reconstruction to remake the third parity drive. A sample extension code called RDP+ is given based on RDP. Moreover, we extended the study to present another extension example called X-code+ which has better update penalty and load balance. The analysis shows that RAID-6Plus is a balanced tradeoff of reliability, performance, and practicality. For instance, RDP+ could achieve speedups as high as 33.4% in comparison to the RTP with conventional rebuild, 11.9% in comparison to RTP with the optimal rebuild, 47.7% in comparison to STAR with conventional rebuild, and 26.2% for a single failure rebuild.