Patent ID: 7136964

Claim:
A disk array system including a plurality of data physical drives and a plurality of spare physical drives, which comprises: a data parity group composed of said plurality of data physical drives; a spare parity group composed of said plurality of spare physical drives, which are used as saving destinations for said plurality of data physical drives; spare logic drive retaining means for retaining a spare logic drive of a desired capacity in said spare parity group, in case a data physical drive to be data-saved exists in said plurality of data physical drives constituting said data parity group, said spare logic drive being not a spare physical drive of said plurality of spare physical drives, but being a logical area created by using at least one of areas of said plurality of spare physical drives; data saving means for saving the data of said data physical drive to be data-saved, in said spare logic drives; and data parity group reconfiguring means for defining virtual physical drives corresponding to said spare logic drives and for removing said data physical drive to be data-saved from said data parity group and incorporating at least one of said virtual physical drives instead of said data physical drive to be data saved into said data parity group.