A New Reconsyruction Algorithm for RAID 5 using Parity Sparing

Abstract

Sparing schemes were proposed to improve the reliability of RAID5 disk arrays. The usage of a spare disk makes the reliability of disk arrays dependent on the reconstruction time during which data of the failed disk are reconsyructed on the spare disk space using the surviving disks. Several reconstruction algorithms have been suggeested for reducing the reconstruction time and thus improving the reliability of disk arrays. Parity sparing shows better performance than other sparing schemes, but the merging process during the reconstruction cause the scheme to have rather long reconstruction time. We propose a new reconstruction algorithm, called variant-block piggybacking, for RAID level 5 using parity sparing. We have found that though variant-block piggbacking degrades performance a little it gramatically reduces reconstruction time and thus improves the reliability of disk arrays using parity sparing.