Patent ID: 7634588

Claim:
A method of controlling data transfer in a switch system which is arranged to be coupled to at least one initiator and with which a plurality of storage devices each having a plurality of disk drives are detachably connectable, wherein said at one least initiator, when coupled to the switch system, is arranged to access the switch system targeting logical units each defined with its unique logical unit identification information, the method comprising: a first status comprising: receiving a first data input request from said at least one initiator for storing data to a target logical unit which is defined with its unique logical unit identification information, and transferring the data under the first data input request to a first one of the storage devices so that the data under the first data input request is input into a storage area of the disk drives of the first storage device; a second status comprising: transferring data stored in the first storage device to a second one of the storage devices; and a third status comprising: receiving a second data input request from said at least one initiator for storing data to said target logical unit, and transferring the data under the second data input request to the second storage device so that the data under the second data input request is input into a storage area of the disk drives of the second storage device, the method further comprising: controlling authorization of reserves such that said at least one initiator is authorized for a reserve if said target logical unit is not reserved by another initiator, wherein the second status is conducted between the first status and the third status such that the data stored in the first storage device is transferred to the second one of the storage devices while said target logical unit is not reserved by an initiator other than said at least one initiator.