Data migration method

• US 20060064466A1
• Filed: 11/04/2004
• Published: 03/23/2006
• Est. Priority Date: 09/22/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Shiga, Kenta, Nakatsuka, Daiki
• Granted Patent: US 7,334,029 B2
• Time in Patent Office: Days
• US Class Current: 709/214
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 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]

Abstract

A system is provided in which a first storage device for managing a target to which a first physical port and a first logical volume are allocated, a second storage device for managing a second logical volume, and a computer for establishing a first communication path with the first physical port and conducting access to the target by using the communication path. The first storage device creates in the second storage devices a target holding an identifier identical to that of the aforementioned target and allocates the second logical volume and a second physical port to the target, and the computer establishes a second communication path with the second physical port and maintains the access to the target by using the second communication path.

Claims

1. A system comprising:

a first device;

a second device;

a third device; and

a network for mutually connecting said first, second, and third devices, wherein

said first device designates to said second device creation of a storage area having an identifier identical to an identifier assigned to a storage area that is owned by the first device itself and accessed by said third device,

said second device creates a storage area having said identifier based on the designation from said first device; and

said third device accesses the storage area owned by said second device by using said identifier.

2. The system according to claim 1, wherein said first device and second device are storage devices, and

said third device is a computer.

3. The system according to claim 1, wherein, said first, second, and third devices are storage devices.

4. The system according to either claim 2 or claim 3, wherein each of said first and second devices has one or more ports, and

said identifier is associated with the combination of one of said ports and said storage area.

5. The system according to claim 4, wherein before the creation of the storage area having said identifier is designated to said second device, said first device replicates data stored in the storage area owned by said first device into the storage area owned by said second device, wherein

when the creation of the storage area having said identifier is designated from said first device, said second device creates the storage area having said identifier by assigning said identifier to the storage area where said replicated data are stored.

6. The system according to claim 5, wherein

said third device

establishes a first communication path with a first port corresponding to said identifier of said first device;

establishes a second communication path with a second port corresponding to said identifier of said second device after the storage area having said identifier has been created in said second device; and

disconnects said first communication path based on the designation of said first device and then conducts communication with said second device by using said second communication path.

7. The system according to claim 6, further comprising a name management device connected to said network, wherein

said second device sends to said name management device information of said second port together with information of said identifier after the creation of the storage area having said identifier;

said name management device notifies said third device that there are changes in information of the storage area corresponding to said identifier based on the information sent from said second device; and

said third device establishes said second communication path with said second port based on the notification from said name management device.

8. The system according to claim 7, wherein

said first device requests said name management device to delete information of association of said first port and said identifier after the storage area having said identifier has been created in said second device.

9. The system according to claim 8, wherein said first device, said second device, and said third device communicate by using the iSCSI protocol.

10. The system according to claim 9, wherein said name management device communicate with said first device, said second device, and said third device by using iSNSP.

11. A data migration method in a system comprising a first storage device comprising a first physical port and a first logical volume and managing a target to which said first physical port and said first logical volume are allocated, a second storage device comprising a second physical port, and a computer for establishing a first communication path with said first physical port and conducting access to said target by using the communication path, said method comprising:

a step in which said first storage device copies data stored in said first logical volume to a second logical volume of said second storage device;

a step in which after completion of said copying, said first storage device designates creation of a target having an identifier identical to that of said target to said second storage device;

a step in which said second storage device allocates said second logical volume and said second physical port to the target;

a step in which said second storage device notifies said computer that said second physical port was anew allocated to said target;

a step in which said computer receives the notification and establishes a second communication path with said second physical port;

a step in which said first storage device deletes the allocation of said first physical port to said target and notifies said computer that said first physical port has been deleted from the allocation of said target; and

a step in which said computer receives said notification, disconnects said first communication path, and maintains the access to said target by using said second communication path.

12. The data migration method according to claim 11, wherein a name management device for storing association of an identifier of a target and a network address is connected to said network, the method further comprising:

a step in which said computer requests said name management device for notification about changes in said association;

a step in which said second storage device registers the association of the identifier of said target and a network address of said second physical port in said name management device; and

a step in which said name management device notifies said computer that said second physical port has been anew allocated to said target by notifying said computer of changes in the association.

13. The data migration method according to claim 12 further comprising:

a step in which said first storage device deletes association of the identifier of said target and a network address of said first physical port from said name management device; and

a step in which said name management device notifies said computer that said first physical port, which was allocated to said target, has been deleted by notifying said computer of changes in the association.

14. The data migration method according to claim 13 further comprising a step in which said first storage device copies the data stored in said first logical volume to said second logical volume of said second storage device by using the iSCSI protocol.

15. A system comprising:

a first storage device comprising a first physical port and a first logical volume and managing a target to which said first physical port and said first logical volume are allocated;

a second storage device comprising a second physical port;

a computer;

and a name management device connected to said first storage device, said second storage device, and said computer via a network, wherein

said computer establishes a first communication path with said first physical port and conducts access to said target by using the communication path;

said first storage device replicates data stored in said first logical volume to a second logical volume of said second storage device;

after completion of said replication, said first storage device designates creation of a target having an identifier identical to that of said target to said second storage device;

said second storage device allocates said second logical volume and said second physical port to the target;

said second storage device notifies said name management device that said second physical port was anew allocated to said target;

said name management device notifies said computer that said second physical port was allocated to said target;

said computer receives the notification and establishes a second communication path with said second physical port;

said first storage device deletes the allocation of said first physical port to said target and notifies said name management device that said first physical port has been deleted from the allocation of said target;

said name management device notifies said computer that the allocation of said first physical port was deleted from said target; and

said computer receives said notification, disconnects said first communication path, and maintains the access to said target by using said second communication path.

16. A device connected to a first device and a second device via a network, comprising:

a control unit;

a storage area;

and a port for connection to said network, wherein

said control unit

replicates data stored in the storage area owned by itself and accessed by said first device into said second device;

designates to said second device creation of a storage area having an identifier identical to an identifier attached to the storage area accessed by said first device; and

after the creation of the storage area in said second device, notifies said first device that correspondence of the port corresponding to said identifier and said identifier has been eliminated.