Apparatus and method for instant copy of data in a dynamically changeable virtual mapping environment

• US 20020053009A1
• Filed: 06/19/2001
• Published: 05/02/2002
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Storage Technologies Corporation (Oracle Corporation)
• Inventors: Milligan, Charles A., Selkirk, Stephen S.
• Granted Patent: US 6,779,094 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/065 Replication 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 system is provided to support dynamically changeable virtual mapping schemes in a data processing system. The present invention separates processing of data unit requirements from the selection of which storage subsystems to use for storage by using a storage methodologies inventory. A stored data management subsystem contains one or more hosts. A plurality of data storage elements is functionally coupled to the one or more hosts. The plurality of data storage elements is organized using a plurality of layers of mapping tables. The plurality of layers of mapping tables provides unique identification of location of the data such that individual data entries in a mapping table is variable and self-defining with respect to the amount of data managed. In addition, the present system provides various instant copy mechanisms for copying data upon receiving a write operation to either a source or copy data. The instant copy mechanisms may be selected based on the type of mapping originally used to store the data that is to be copied.

Claims

1. A method of performing an instant copy of data, comprising:

receiving a write operation for writing new data to a first data location in one of an initial physical storage area and an additional physical storage area; and

writing the new data to a second data location in the additional physical storage area regardless of whether the first data location is in the initial physical storage area or the additional physical storage area.

2. The method of claim 1, further comprising generating a pointer to the new data in the second data location.

3. The method of claim 1, wherein the additional physical storage area contains a combination of new data for original data in the initial physical storage area and new data for copy data in the additional physical storage area.

4. The method of claim 3, wherein meta-data associated with the additional physical data area include a first set of pointers pointing to new data for original data in the initial physical storage area and a second set of pointers pointing to new data for copy data in the additional physical storage area.

5. The method of claim 4, wherein each of the pointers in the first set of pointers are linked to one another.

6. The method of claim 4, wherein each of the pointers in the second set of pointers are linked to one another.

7. The method of claim 3, further comprising separating the original data from the copy data.

8. The method of claim 7, wherein separating the original data from the copy data includes determining a first amount of new data for the original data that is present in the additional physical storage device and a second amount of new data for the copy data that is present in the additional physical storage device.

9. The method of claim 8, further comprising comparing the first amount to the second amount and copying one of the new data for the original data and the new data for the copy data to the initial physical storage device based on the comparison.

10. The method of claim 9, wherein the new data for the original data is copied to the initial physical storage device if the first amount is less than the second amount.

11. The method of claim 9, wherein the new data for the copy data is copied to the initial physical storage device if the second amount is less than the first amount.

13. The computer program product of claim 12, further comprising third instructions for generating a pointer to the new data in the second data location.

14. The computer program product of claim 12, wherein the additional physical storage area contains a combination of new data for original data in the initial physical storage area and new data for copy data in the additional physical storage area.

15. The computer program product of claim 14, wherein meta-data associated with the additional physical data area include a first set of pointers pointing to new data for original data in the initial physical storage area and a second set of pointers pointing to new data for copy data in the additional physical storage area.

16. The computer program product of claim 15, wherein each of the pointers in the first set of pointers are linked to one another.

17. The computer program product of claim 15, wherein each of the pointers in the second set of pointers are linked to one another.

18. The computer program product of claim 14, further comprising third instructions for separating the original data from the copy data.

19. The computer program product of claim 18, wherein the third instructions for separating the original data from the copy data include instructions for determining a first amount of new data for the original data that is present in the additional physical storage device and instructions for determining a second amount of new data for the copy data that is present in the additional physical storage device.

20. The computer program product of claim 19, wherein the third instructions for separating the original data from the copy data further includes instructions for comparing the first amount to the second amount and instructions for copying one of the new data for the original data and the new data for the copy data to the initial physical storage device based on the comparison.

21. The computer program product of claim 20, wherein the new data for the original data is copied to the initial physical storage device if the first amount is less than the second amount.

22. The computer program product of claim 20, wherein the new data for the copy data is copied to the initial physical storage device if the second amount is less than the first amount.

12. A computer program product in a computer readable medium for performing an instant copy of data, comprising:

first instructions for receiving a write operation for writing new data to a first data location in one of an initial physical storage area and an additional physical storage area; and

second instructions for writing the new data to a second data location in the additional physical storage area regardless of whether the first data location is in the initial physical storage area or the additional physical storage area.

23. An apparatus for performing an instant copy of data, comprising:

means for receiving a write operation for writing new data to a first data location in one of an initial physical storage area and an additional physical storage area; and

means for writing the new data to a second data location in the additional physical storage area regardless of whether the first data location is in the initial physical storage area or the additional physical storage area.