Data-migration method
First Claim
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.
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Accused Products
Abstract
A method of migrating data from an old storage subsystem to a new storage subsystem in a data processing system which comprises host computers and storage subsystems. There is provided a route-changing phase before the data is migrated from the old storage subsystem to the new storage subsystem. In the route-changing phase, each host computer can access both the old and new storage subsystems and the new storage subsystem writes data into the old storage subsystem in response to a write request from the host computer and reads data from the old storage subsystem and sends the data to the host computer in response to a read request from the host computer.
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Citations
13 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. 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 connected to said plurality of host computers, said method comprising the steps of:
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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 said host computers to include route-changed host computers accessing said new storage subsystem and route-unchanged host computers accessing said old storage subsystem, 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 route-changed host computer and sending the data to said route-changed host computer, in said route changing phase, by said new storage subsystem, writing data into said old storage subsystem in response to a write request from said route-changed host computer and informing said route changed host computer of completion of processing after ascertaining completion of data-writing processing, in said route changing phase, by said old storage subsystem, reading data and sending the data to a route changed host computer in response to a read request from said route-unchanged host computer, and in said route changing phase, by said old storage subsystem, writing data in response to a write request from said route-unchanged host computer and informing said route-changed host computer of completion of processing after ascertaining completion of data-writing processing.
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Specification