Patent ID: 7127581
Filing Date: 2006-10-24
Classification: G06F

Abstract:
1. A method of migrating data from an old storage subsystem to a new storage subsystem in a data processing system which includes a plurality of host computers and a plurality of storage subsystems said method comprising the steps of: conducting a route-changing phase before migration of the data from the old storage subsystem to the new storage subsystem; in said route-changing phase, sequentially changing an indication of access destination storage subsystems in said host computers such that an indication of the access destination storage subsystem of a first host computer is changed from said old storage subsystem to said new storage subsystem, an indication of the access destination storage subsystem of a second host computer is unchanged from said old storage subsystem to said new storage subsystem, and then an indication of the access destination storage subsystem of the second host computer is changed from said old storage subsystem to said new storage subsystem after the access destination storage subsystem of the first host computer has been changed, thereby permitting each host computer to access both the old and new storage subsystems; and in said route changing phase, by said new storage subsystem, reading data from said old storage subsystem in response to a read request from a said first host computer, sending the data to said first host computer, and writing data into said old storage subsystem in response to a write request from said first host computer.