In a system management apparatus, a failure detection unit detects a readout failure in one of blocks constituting distributed data stored in a first RAID disk array. A request unit requests a computer to supplement one of the blocks of the distributed data stored in the first RAID disk array in which a readout failure irrecoverable by use of only the data stored in the first RAID disk array occurs, where the computer has a second RAID disk array storing a duplicate of the distributed data stored in the first RAID disk array. And an overwriting unit receives data corresponding to the one of the blocks from the computer, and overwrites the one of the blocks with the received data.