Patent ID: 8103843

Claim:
A storage system comprising: a storage device which configures an original volume for storing data which is read/written by a host, a copy volume for storing a copy of the original volume at a predetermined timing, and a snapshot volume for storing a snapshot data which is a snapshot of the original volume; and a controller which controls access from the host to the storage device; wherein the controller: copies data of the original volume to the copy volume upon reception of a request of copying the original volume; creates the snapshot volume of the original volume each time of reception of a snapshot creation request, wherein each of the plurality of the snapshot volumes stores a snapshot of different generation; stores the snapshot data in the snapshot volume corresponding to a write request to the original volume; manages a generation of the stored snapshot in the plurality of the snapshot volumes according to predetermined copy volume blocks and snapshot volume blocks, and manages a generation of the copy volume; and reads data from the snapshot volume or the copy volume when a read request to a volume of a generation different from that of the original volume is received from the host.