Storage system and controller for controlling remote copying

• US 20080109620A1
• Filed: 01/03/2007
• Published: 05/08/2008
• Est. Priority Date: 11/08/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nabekura, Yukoh
• Granted Patent: US 7,707,375 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• 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 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

The reconfiguration controller selects for each data whether or not to execute remote copying of data from the first storage device to the second storage device. Each data sent from the host to be stored in the first storage device contains a copy policy tag that defines the policy relating to remote copying. The reconfiguration controller determines whether or not remote copying of the each data is necessary based on the copy policy tag of the each data, and selectively transmits the data requiring remote copying to the second storage device.

Claims

1. A storage system which comprises a first storage device that receives and stores at least one data set from a host, and a second storage device that receives and stores the at least one data set transmitted from the first storage device, and in which remote copying of the data set stored in the first storage device to the second storage device can be executed, wherein

the each data set stored in the first storage device has a copy policy tag that defines a policy relating to the remote copying of the data set,

the storage system further comprising a reconfiguration controller that selects whether or not to transmit the data set stored in the first storage device to the second storage device based on the copy policy tag of the each data set stored in the first storage device.

2. The storage system according to claim 1, wherein the reconfiguration controller is built into the first storage device.

3. The storage system according to claim 1, wherein the reconfiguration controller is located outside of the first storage device and the second storage device, receives each data set stored in the first storage device from the first storage device, and selects whether or not to transmit the data set received from the first storage device to the second storage device based on the copy policy tag of the data set received from the first storage device.

4. The storage system according to claim 1, wherein the copy policy tag of the each data set comprises an element that designates whether or not remote copying of the data set is enabled, and the reconfiguration controller selectively transmits to the second storage device the data set having the copy policy tag that designates remote copy enabled.

5. The storage system according to claim 1, wherein the copy policy tag of the each data set comprises an element that designates conditions for requiring remote copying of the data set, and the reconfiguration controller determines whether or not the data set fulfills the conditions designated by the copy policy tag, and selectively transmits to the second storage device the data set that fulfills the conditions.

6. The storage system according to claim 5, wherein the conditions comprise an access counter set value, and the reconfiguration controller detects the access frequency of the each data set, and determines whether or not the conditions are fulfilled by comparing the detected access frequency with the set value designated by the copy policy tag of the data set.

7. The storage system according to claim 1, wherein the copy policy tag of the each data set comprises an element that designates whether or not the data set can be overwritten, and

(A) when attempting to transmit to the second storage device current data having the copy policy tag designating overwrite enabled, and if update data to the current data is received prior to transmitting the current data to the second storage device, the reconfiguration controller transmits the update data to the second storage device without transmitting the current data to the second storage device, and

(B) when attempting to transmit to the second storage device current data having the copy policy tag designating overwrite disabled, and if update data to the current data is received prior to transmitting the current data to the second storage device, the reconfiguration controller transmits the update data to the second storage device after the current data is transmitted to the second storage device.

8. The storage system according to claim 1, wherein the copy policy tag of the each data set comprises an element designating whether or not a transmission designation command input from a user is valid, and if the transmission designation command from the user is input, the reconfiguration controller selectively transmits to the second storage device the data set having the copy policy tag that designates that the transmission designation command is valid.

9. The storage system according to claim 1, wherein the first storage device checks whether or not the reconfiguration controller is in the busy state, and if the reconfiguration controller is in the busy state, the first storage device transmits, among the data sets stored in the first storage device, the data set not yet handled by the reconfiguration controller directly to the second storage device without passing through the reconfiguration controller.

10. The storage system according to claim 1, wherein the reconfiguration controller checks whether or not there are mismatches of the copy policy tags between a plurality of data sets belonging to the same data group within the data sets stored in the first storage device, and if mismatches of the copy policy tags are detected, the same processing relating to whether or not to transmit to the second storage device is applied to all of the plurality of data sets belonging to the same data group.

11. The storage system according to claim 1, further comprising a policy tagger that attaches the copy policy tag to the each data set stored in the first storage device.

12. The storage system according to claim 11, wherein the policy tagger is provided in the host.

13. The storage system according to claim 11, wherein the policy tagger is provided in the first storage device.

14. The storage system according to claim 11, wherein the policy tagger attaches the copy policy tag of the same content to all of the plurality of data sets belonging to the same data group.

15. A controller in a storage system comprising first and second storage devices, which controls remote copying of data sets stored in the first storage device to the second storage device, wherein

each data set stored in the first storage device has a copy policy tag that defines the policy relating to the remote copying of the data set, and

the controller selects whether or not to transmit the data set stored in the first storage device to the second storage device based on the copy policy tag of the data set stored in the first storage device.

16. A method for controlling remote copying of data sets stored in a first storage device to a second storage device in a storage system comprising the first and second storage devices, the method comprising the steps of:

attaching to the each data set stored in the first storage device a copy policy tag that defines the policy relating to remote copying of the data set, and

the controller selecting whether or not to transmit the data set stored in the first storage device to the second storage device based on the copy policy tag of the data set stored in the first storage device.