A Hybrid Approach of Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation
Prof Yinlong Xu (School of Computer Science and Technology University of Science and Technology of China )
COMPUTER SCIENCE SEMINARDATE: 2013-11-28
TIME: 10:30:00 - 11:30:00
LOCATION: CSIT Seminar Room, N101
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ABSTRACT:
The current parallel storage systems use thousands of inexpensive disks to meet the storage requirement of applications. Data redundancy and/or coding are used to enhance data availability, e.g., Row-diagonal parity (RDP) and EVENODD codes, which are widely used in RAID-6 storage systems, provide data availability with up to two disk failures. To reduce the probability of data unavailability, whenever a single disk fails, disk recovery will be carried out. We find that the conventional recovery schemes of RDP and EVENODD codes for a single failed disk only use one parity disk. However, there are two parity disks in the system, and both can be used for single disk failure recovery. In this paper, we propose a hybrid recovery approach which uses both parities for single disk failure recovery and design efficient recovery schemes for RDP code (RDOR-RDP) and EVENODD code (RDOR-EVENODD). Our recovery scheme has the following attractive properties: (1) read optimality in the sense that our scheme issues the smallest number of disk reads to recover a single failed disk and it reduces approximately 1/4 of disk reads compared with conventional schemes; (2) load balancing property in that all surviving disks will be subjected to the same (or almost the same) amount of additional workload in rebuilding the failed disk.
BIO:
Yinlong Xu received his B.S. in Mathematics from Peking University, and MS and Ph.D both in Computer Science from University of Science & Technology of China(USTC) in. He is currently a professor and Deputy Dean with the School of Computer Science & Technology at USTC. Prior to that, he served the Department of Computer Science & Technology at USTC as assistant professor, lecturer, and associate professor. He is currently leading a research group working on distributed storage and high performance computing. His research interests include network coding, distributed storage, high performance computing, wireless network, etc. He received the Excellent Ph.D Advisor Award of Chinese Academy of Sciences in 2006.
