Patent ID: 7519787

Claim:
A management method for a computer system comprising at least one host computer, at least one storage system coupling with said host computer, and a management computer coupling with the host computer and the storage system, wherein said storage system comprises a physical disk for storing data sent from the host computer and a disk controller for controlling input or output of the data to or from the physical disk; wherein the disk controller provides the host computer with a thin provisioning volume to which a storage area of the physical disk is to be allocated in response to a write request sent from said host computer; wherein said host computer recognizes the thin provisioning volume as a volume having a capacity bigger than a capacity of the storage area of the physical disk allocated to the thin provisioning volume, said management method comprising: obtaining from the disk controller a first capacity of the storage area of the physical disk allocated to the thin provisioning volume by using a first volume identifier, the first volume identifier to be used to identify the thin provisioning volume by said storage system, obtaining from the host computer a second capacity of the storage area of the physical disk used by the host computer by using a second volume identifier, the second volume identifier being used to identify the thin provisioning volume by the host computer, calculating an excess allocation capacity allocated to the thin provisioning volume by subtracting the second capacity from the first capacity, calculating an excess allocation ratio by dividing the calculated excess allocation capacity by the first capacity, and displaying the calculated excess allocation ratio.