Data-migration method

• US 7,269,703 B2
• Filed: 09/08/2006
• Issued: 09/11/2007
• Est. Priority Date: 01/13/2004
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Watanabe, Naoki
• Primary Examiner(s): PORTKA, GARY J
• Application Number:
  US11/517,386
• Publication Number:
  US 20070101084A1
• Time in Patent Office: 368 Days
• Field of Search: None
• US Class Current: 711/165
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/076 by exceeding a count or rate limit, e.g. word- or bit count limit
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

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.

Claims

1. A method of migrating logical volumes of 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 each other by a network, said old storage subsystem including a plurality of logical volumes to be migrated to said new storage subsystem, said logical volumes being divided into a plurality of groups of logical volumes, said method comprising the steps of:

conducting an un-transferred phase including pairing said groups of logical volumes in said old storage subsystem to groups of logical volumes in said new storage subsystem and connecting said new storage subsystem to the network;

conducting a route-changing phase before migration of the logical volumes from the old storage subsystem to the logical volumes of said new storage subsystem;

in said route-changing phase, sequentially changing indications of access destination storage subsystems in said host computers such that the indications of the access destination storage subsystems of said host computers are sequentially changed from said old storage subsystem to said new storage subsystem, thereby permitting each host computer to access both the old and new storage subsystems;

conducting a data transferring phase including sequentially transferring on a group basis said groups of logical volumes from said old storage subsystem to said new storage subsystem; and

conducting a transferred phase including disconnecting said old storage subsystem from the network and conducting all accesses to said new storage subsystem,

wherein information indicating relationships between each of said phases and identifiers of the groups of logical volumes on the old storage subsystem and the new storage subsystem are stored in a table which is stored in a management system connected to the old storage subsystem and the new storage subsystem, and

wherein said route changing phase and said data transferring phase are conducted according to groups of logical volumes based on said information indicating relationships in said table.

2. A method of migrating logical volumes of data according to claim 1, wherein all groups of logical volumes are in said un-transferred phase.

3. A method of migrating logical volumes according to claim 1, wherein at least one groups of logical volumes is in said route change phase and the remaining groups of logical volumes are in the un-transferred phase.

4. A method of migrating logical volumes according to claim 1, wherein at least one of the groups of logical volumes is in the data transferring phase, at least one of the groups of logical volumes is in the route changing phase and the remaining groups of logical volumes are in the un-transferred phase.

5. A method of migrating logical volumes according to claim 1, wherein at least one of the groups of logical volumes is in the transferred phase, at least one of the groups of logical volumes is in the data transferring phase, at least one of the groups of logical volumes is in the route changing phase and the remaining groups of logical volumes are in the un-transferred phase.

8. A method of migrating logical volumes according to claim 1, wherein an indication of an access destination storage subsystem of a first host computer is changed from said old storage system to said new storage system, an indication of the access destination storage system of a second host computer is changed 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 said old and said new storage subsystems.

9. A method of migrating logical volumes according to claim 8, wherein 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 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 host computer.

6. A method of migrating logical volumes of 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 each other by a network, said old storage subsystem including a plurality of logical volumes to be migrated to said new storage subsystem, said logical volumes being divided into a plurality of groups of logical volumes, said method comprising the steps of:

conducting an un-transferred phase including pairing said groups of logical volumes in said old storage subsystem to groups of logical volumes in said new storage subsystem and connecting said new storage subsystem to the network;

conducting a route-changing phase before migration of the logical volumes from the old storage subsystem to the logical volumes of said new storage subsystem;

in said route-changing phase, sequentially changing indications of access destination storage subsystems in said host computers such that the indications of the access destination storage subsystems of said host computers are sequentially changed from said old storage subsystem to said new storage subsystem, thereby permitting each host computer to access both the old and new storage subsystems;

conducting a data transferring phase including sequentially transferring on a group basis said groups of logical volumes from said old storage subsystem to said new storage subsystem; and

conducting a transferred phase including disconnecting said old storage subsystem from the network and conducting all accesses to said new storage subsystem,

wherein at least one of the groups of logical volumes is in the transferred phase, at least one of the groups of logical volumes is in the data transferring phase, at least one of the groups of logical volumes is in the route changing phase and the remaining groups of logical volumes are in the un-transferred phase,

wherein relationships are formed in a table which is stored in a management system connected to the old storage subsystem and the new storage subsystem, and

wherein the information indicating the relationships are formed in a display screen of the management system connected to said old storage subsystem and said new storage subsystem.

7. A method of migrating logical volumes according to claim 6, wherein an indication of an access destination storage subsystem is displayed on a display screen of the management system.

10. A data processing system comprising:

a plurality of host computers;

a plurality of storage subsystems; and

a migration control host controlling migration of logical volumes of data from an old storage subsystem to a new storage subsystem, said logical volumes being divided into a plurality of groups of logical volumes; and

a network which connects said host computers, said storage subsystems and said migration control host to each other,

wherein said migration control host performs control including;

conducting an un-transferred phase including pairing said groups of logical volumes in said old storage subsystem to groups of logical volumes in said new storage subsystem and connecting said new storage subsystem to the network,

conducting a route-changing phase before migration of the logical volumes from the old storage subsystem to the logical volumes of said new storage subsystem,

in said route-changing phase, sequentially changing an indications of access destination storage subsystems in said host computers such that the indications of the access destination storage subsystems of said host computers are sequentially changed from said old storage subsystem to said new storage subsystem, thereby permitting each host computer to access both the old and new storage subsystems,

conducting a data transferring phase including sequentially transferring, on a group basis, said groups of logical volumes from said old storage subsystem to said new storage subsystem, and

conducting a transferred phase including disconnecting said old storage subsystem from the network and conducting all accesses to said new storage subsystem,

wherein information indicating relationships between each of said phases and identifiers of the groups of logical volumes on the old storage subsystem and the new storage subsystem are stored in a table which is stored in a management system connected to the old storage subsystem and the new storage subsystem, and

wherein said route changing phase and said data transferring phase are conducted according to groups of logical volumes based on said information indicating relationshios in said table.

11. A data processing system according to claim 10, wherein all groups of logical volumes are in said un-transferred phase.

12. A data processing system according to claim 10, wherein at least one groups of logical volumes is in said route changing phase and the remaining groups of logical volumes are in the un-transferred phase.

13. A data processing system according to claim 10, wherein at least one of the groups of logical volumes is in the data transferring phase, at least one of the groups of logical volumes is in the route changing phase and the remaining groups of logical volumes are in the un-transferred phase.

14. A data processing system according to claim 10, wherein at least one of the groups of logical volumes is in the transferred phase, at least one of the groups of logical volumes is in the data transferring phase, at least one of the groups of logical volumes is in the route changing phase and the remaining groups of logical volumes are in the un-transferred phase.

16. A data processing system according to claim 10, wherein an indication of an access destination storage subsystem of a first host computer is changed from said old storage system to said new storage system, an indication of the access destination storage system of a second host computer is changed 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 said old and said new storage subsystems.

17. A data processing system according to claim 16, wherein 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 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 host computer.

15. A data processing system comprising:

a plurality of host computers;

a plurality of storage subsystems; and

a migration control host controlling migration of logical volumes of data from an old storage subsystem to a new storage subsystem, said logical volumes being divided into a plurality of groups of logical volumes; and

a network which connects said host computers, said storage subsystems and said migration control host to each other,

wherein said migration control host performs control including;

conducting an un-transferred phase including pairing said groups of logical volumes in said old storage subsystem to groups of logical volumes in said new storage subsystem and connecting said new storage subsystem to the network,

conducting a route-changing phase before migration of the logical volumes from the old storage subsystem to the logical volumes of said new storage subsystem,

in said route-changing phase, sequentially changing indications of access destination storage subsystems in said host computers such that the indications of the access destination storage subsystems of said host computers are sequentially changed from said old storage subsystem to said new storage subsystem, thereby permitting each host computer to access both the old and new storage subsystems,

conducting a data transferring phase including sequentially transferring on a group basis said groups of logical volumes from said old storage subsystem to said new storage subsystem, and

conducting a transferred phase including disconnecting said old storage subsystem from the network and conducting all accesses to said new storage subsystem,

wherein information is stored indicating relationships between each of said phases and identifiers of the groups of logical volumes on the old storage subsystem and the new storage subsystem;

a management system connected to said old storage subsystem and said new storage subsystem,

wherein the information indicating the relationships are formed in a table which is stored in said management system, and

wherein the information indicating the relationships of the table are displayed on a display screen of the management system.