A New Minimum Density RAID-6 Code with a Word Size of Eight

James S. Plank

The 7th IEEE International Symposium on Network Computing and Applications (IEEE NCA08), Cambridge, MA, July, 2008.

PDF: http://web.eecs.utk.edu/~plank/plank/papers/NCA-2008.pdf


Abstract

RAID-6 storage systems protect k disks of data with two parity disks so that the system of k+2 disks may tolerate the failure of any two disks. Coding techniques for RAID-6 systems are varied, but an important class of techniques are those with minimum density, featuring an optimal combination of encoding, decoding and modification complexity. The word size of a code impacts both how the code is laid out on each disk's sectors and how large k can be. Word sizes which are powers of two are especially important, since they fit precisely into file system blocks. Minimum density codes exist for many word sizes with the notable exception of eight. This paper fills that gap by describing new codes for this important word size. The description includes performance properties as well as details of the discovery process.

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