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A Hybrid Approach to Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation
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| Venue: | ACM Trans. on Storage |
| Citations: | 11 - 3 self |
BibTeX
@ARTICLE{Xiang_ahybrid,
author = {Liping Xiang and Yinlong Xu and John C. S. Lui and Qian Chang and Yubiao Pan and Runhui Li},
title = {A Hybrid Approach to Failed Disk Recovery Using RAID-6 Codes: Algorithms and Performance Evaluation},
journal = {ACM Trans. on Storage},
year = {},
pages = {2011}
}
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Abstract
The current parallel storage systemsuse thousandsof inexpensive disks to meet the storage requirement of applications.Dataredundancyand/orcodingareusedtoenhancedataavailability,e.g., Row-diagonalparity (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 forasinglefaileddisk onlyuseone paritydisk.However, there are twoparitydisks inthesystem,and bothcan be usedfor singledisk failure recovery. Inthispaper, wepropose a hybrid recovery approach which uses both parities for single disk failure recovery and we 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. We carry out performance evaluation to quantify the merits of RDOR-RDP and RDOR-EVENODD on some widely used disks with DiskSim. The off-line experimental results show that RDOR-RDP and RDOR-
Keyphrases
performance evaluation hybrid approach evenodd code disk read data availability twoparitydisks inthesystem additional workload conventional scheme recovery scheme disk recovery single disk failure recovery conventional recovery scheme usedfor singledisk failure recovery single failed disk hybrid recovery approach dataredundancyand orcodingareusedtoenhancedataavailability current parallel storage systemsuse efficient recovery scheme failed disk data unavailability raid-6 storage system scheme issue rdp code storage requirement inexpensive disk single disk fails disk failure off-line experimental result following attractive property
