The storage controller 10 transmits response information indicating that the data has been stored, to the host devices 2 (step S107). Then the storage controller 10 determines whether the user data for one stripe row 41 has been recorded or not (step S108).

If the user data for one stripe row 41 has not been recorded, the storage controller 10 ends the processing. If the user data for one stripe row 41 has been recorded, by contrast, the storage controller 10 generates the redundant data from the user data for one stripe row 41 and carries out destage processing including storing the user data and the redundant data in the SSD 20 (step S109). In the destage processing, the storage controller 10 records the redundant data in the entry 42 having the attribute 514 of the parity area in the stripe row 41 in which the user data is recorded, for instance. The storage controller 10 stores the data recorded in each entry 42 in the relevant stripe row 41, in the SSD block 21 identified by the SSD ID 515 and the SSD block ID 516 that correspond to the entry ID 513 for identification of the entry 42, based on the extent configuration management table 510.