When rebuilding a RAID (Redundant Array of Independent Disks) array in which a drive has failed, if another RAID array contains a mirror copy of the of the rebuilding RAID array content, this mirroring RAID array can be used to more rapidly rebuild the RAID array with the failed drive. Data requests to the rebuilding RAID array can be redirected to the mirroring RAID array; data can be transferred from the mirroring RAID array; or a combination of these can be used to finish rebuilding more quickly. When transferring data to the rebuilding array from the mirroring array, the transfer can be performed as a direct memory access (DMA) process independently of the RAID module of either array.