Patent ID: 8214615

Claim:
A computer system comprising: a management server; a first storage system comprising a first logical device, wherein the first storage system is coupled to a host computer and the management server, and provides the first logical device to the host computer; a second storage system coupled to the host computer and the management server; a third storage system coupled to the first storage system and the second storage system, and providing a third logical device, and including a physical storage area storing data sent from the host computer and allocated to the third logical device, wherein a first attribute is set in the first logical device in the first storage system, wherein when a virtualization definition is set in the first logical device in the first storage system to virtualize the third logical device in the third storage system to provide the third logical device to the host computer through the first storage system, the management server receives a request for migrating the first logical device to the second storage system, wherein the management server defines a second logical device in the second storage system to virtualize the third logical device in the third storage system to provide the third logical device to the host computer through the second storage system, wherein the management server obtains the first attribute which is set in the first logical device from the first storage system, and sets the first attribute in the second logical device in the second storage system, wherein the management server provides instructions to cancel the virtualization definition of the first logical device so as to stop virtualizing the third logical device in the third storage system to provide the third logical device to the host computer through the first storage system, and wherein the management server receives the request for migrating the first logical device to the second storage system when access to the third logical device of the third storage system via the first storage system has failed.