Patent ID: 7310713
Filing Date: 2007-12-18
Classification: G06F,Y10S

Abstract:
1. A first storage system coupled to a computer and coupled to a second storage system, the first storage system comprising: a first target device to be accessed by the computer; a logical device allocated to the first target device; and a command device, wherein the logical device is also allocated to a second target device in the second storage system such that the first target device in the first storage system is allocated to the second target device in the second storage system through the logical device such that data sent from the computer is stored in the second storage system via the first storage system; wherein, in response to receiving, at the command device, a read only attribute assignment instruction for assigning a read only attribute to the second target device in the second storage system from the computer, the first storage system controls to set the read only attribute to the second target device, wherein, if the command device receives a command from the computer to change a relationship between the logical device and the second target device after setting the read only attribute, a first relation between the second target device and the logical device is changed to a second relation between a third target device in the second storage system and the logical device in the first storage system, the command includes information identifying the third target device in the second storage system, and wherein, after changing the first relation to the second relation, the first target device in the first storage system is allocated to the third target device in the second storage system through the logical device in the first storage system instead of being allocated to the second target device.