Patent ID: 8190846

Claim:
A storage system coupled to a computer and a management computer, comprising: storage devices accessed by the computer; and a control unit for controlling the storage devices and external storage devices coupled to the storage system, wherein a 1 st first-type logical device corresponding to a storage area that is set in at least one of the storage devices and a 2 nd first-type logical device different in an access characteristic and corresponding to a storage area that is set in at least one of the external storage device, and a second-type logical device that is a virtual storage area are provided, wherein the control unit: sets at least two of the first-type logical devices as storage areas included in a storage pool through mapping; sets the second-type logical device to be accessible by the computer if the storage area of the second type logical device is allocated in response to access to the second-type logical device from the computer; allocates the storage area of the second-type logical device to the storage area of the 1 st first-type logical device if the second-type logical device is not allocated in response to access to the second-type logical device is not allocated in response to access to the second-type device from the computer; and changes the access characteristic of the second-type logical device by changing the allocated storage area of the second-type logical device to a storage area of the 2nd first-type logical device based on static information for the storage pool.