Patent ID: 8707090

Claim:
A storage system connected to a host computer, comprising: a processor; a plurality of drives; and a logical volume which is provided by the plurality of drives and which serves as a target of an I/O request from the host computer, wherein the plurality of drives comprise a plurality of stripe rows which are each configured from a predetermined number of stripe data which are obtained by dividing data which is written to the logical volume by each of the plurality of drives, and first and second redundant data which are generated on the basis of the stripe data, wherein the processor updates the first redundant data and the stripe data of the corresponding stripe rows in correspondence with an update of the write data of the logical volume, and wherein the processor updates the second redundant data on the basis of the predetermined number of stripe data which belong to stripe rows which are the same as the updated stripe data with different timing from the update of the stripe data of the stripe rows.