Storage device and method of accessing copy destination data

A storage device that copies copy source data stored in a copy source volume to a copy destination volume and manages copied data in units of generations, the storage device comprising:

• a storing unit that, for data of each area of the copy source volume, stores presence/no-presence of a copy for each area of the copy destination volume in association with generation information in which a plurality of generations is packaged;
• and
• a processor that is programmed to access, when receiving an access request for a copy destination volume, data of an area for which an access is requested by using the presence/no-presence of a copy stored in the storing unit.

A method of accessing copy destination data that is performed by a storage device that copies copy source data stored in a copy source volume to a copy destination volume and manages copied data in units of generations, the method comprising:

• determining, when receiving an access request for a copy destination volume, presence/no-presence of a copy of a logical address for which the access request is made by using information which is stored in a first storing unit, the first storing unit storing information representing presence/no-presence of a copy in association with a logical address of the copy destination volume in units of generations;
• and
• accessing a physical address of the copy destination volume acquired from a second storing unit for a generation designated by a result of the determining, the second storing unit storing a physical address of the copy destination volume that corresponds to the logical address in units of generations.