Low-redundancy two-dimensional RAID arrays

Most extant two-dimensional RAID arrays tend to use a square matrix organization such that each row and each column of the array forms a parity stripe. These arrays require 2k parity disks to protect the contents of k² data disks against all double disk failures and most triple disk failures. We investigate the reliability of a lesser known organization that allows k parity disks to protect k(k - 1)/2 data disks against all double and most triple failures. We found that this organization can provide the same or better mean times to data loss (MTTDLs) than organizations requiring more parity disks to protect the same number of data disks.