Abstract: A disk array apparatus includes first and second RAID (Redundant Arrays of Inexpensive Disks) groups; and a disk array controller. The first RAID groups includes a first data disk group of a first disk group and a second disk group which store first and second data, respectively; and a first redundant disk configured to store a first redundant data for the first and second data. The second RAID groups includes a second data disk group of a third disk group and a fourth disk group which store second data, respectively; and a second redundant disk configured to store second redundant data for the third and fourth data. Each of the first to fourth disk group includes at least one disk. The disk array controller includes a RAID configuration managing section configured to reconfigure the first to fourth disk groups other than a first specific disk and the first and second redundant disks into a third RAID group when the first specific disk which stores a first specific data is failed in the fourth disk group.