Patent ID: 7757058
Filing Date: 2010-07-13
Classification: G06F,Y10S

Abstract:
1. A storage system coupled to a computer and an external storage system, the storage system comprising: a plurality of first physical storage devices storing data sent from the computer; a first storage controller managing a target device to be accessed by the computer, a first logical device allocated to the target device, a second logical device configured by the first physical storage devices; a command device; and an external storage connection adapter connected to the external storage system, which includes a second storage controller and a plurality of second physical storage devices storing data sent from the storage system, the second storage controller managing a first external target device and a second external target device both of which are configured by the second physical storage devices, wherein the first storage controller allocates the first external target device in the external storage system to the first logical device, wherein if the command device receives a first command, the first storage controller detaches allocation of the first logical device to the target device and then attaches the second logical device to the target device so that the computer can access the second logical device allocated to the target device instead of the first logical device, and wherein if the command device receives a second command, the first storage controller detaches allocation of the first external target device to the first logical device and then attaches the second external target device to the first logical device so that the computer can access the second external target device in the external storage system instead of the first external target device.