Patent ID: 8639898

Claim:
A storage apparatus for providing a first virtual volume including a plurality of first blocks, the storage apparatus in communication with another storage apparatus so as to copy the data thereto, the another apparatus providing a second virtual volume including at least a second block corresponding to the one of the plurality of first blocks, the storage apparatus comprising: a storage unit having a plurality of storage areas, each of storage areas being allocatable as one of the plurality of first blocks; a memory storing information indicating a relationship between each of the first blocks and each of the storage areas, at least one of the storage areas being allocated to the one of the plurality of first blocks according to a usage pattern of the first virtual volume; and a controller configured to receive an instruction for copying data stored in the first virtual volume to the second virtual volume, determine whether each of the first blocks is allocated to any of the storage areas in reference to the information, transmit first data stored in the at least one of the first storage areas to the another apparatus if the first block is allocated to the one of the first storage areas, and transmit second data indicating that other ones of the plurality of first blocks are not allocated to any of the first storage areas to the another apparatus if the one of the plurality of first blocks is not allocated to any of the storage areas.