Patent ID: 7366853

Claim:
A virtualization system for controlling data transfer, said virtualization system being coupled to a host system and a plurality of storage systems, the host system sending an input request including volume identification information for writing data to a first virtual volume in the virtualization system, each of the storage systems comprising a plurality of disk drives and a plurality of logical volumes related to the disk drives, the virtualization system comprising: at least one first port coupled to the host system; at least one second port coupled to the storage systems; and at least one processing circuit; wherein the virtualization system controls to perform first processes of: receiving a first input request, the first input request being sent from the host system and including the volume identification information, and transferring data of the first input request to a first logical volume of a first storage system of the storage systems, the first logical volume being related to the first virtual volume having a status, in which data of an input request including the volume identification information is written to the first virtual volume, so that the first storage system can write the data of the first input request to a storage area of the disk drives related to the first logical volume; wherein the virtualization system controls to perform second processes of: copying data from the first virtual volume to a second virtual volume in the virtualization system, the second virtual volume being related to a second logical volume of a second storage system of the storage systems, receiving a second input request during the copying process, the second input request being sent from the host system and including the volume identification information, and changing a status of the second virtual volume to a status, in which data of an input request including the volume identification information is written to the second virtual volume, on a virtual volume basis; and wherein the virtualization system controls to perform third processes of: receiving a third input request, the third input request being sent from the host system and including the volume identification information, and transferring data of the third input request to the second logical volume of the second storage system so that the second storage system can write the data of the third input request to a storage area of the disk drives related to the second logical volume, wherein data of the second input request is written to the second virtual volume.