Apparatus and method for dynamically changeable virtual mapping scheme

• US 20020178335A1
• Filed: 06/19/2001
• Published: 11/28/2002
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Storage Technologies Corporation (Oracle Corporation)
• Original Assignee: Storage Technologies Corporation (Oracle Corporation)
• Inventors: Milligan, Charles A., Selkirk, Stephen S.
• Granted Patent: US 6,804,755 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/065 Replication mechanisms
• 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:

determining a mapping of the data;

determining an instant copy operation based on the mapping of the data; and

performing an instant copy of the data using the instant copy operation.

2. The method of claim 1, wherein determining a mapping of the data includes parsing extents of the data into sets based on types of mapping used to map the extents.

3. The method of claim 2, wherein determining an instant copy operation based on the mapping of the data includes setting up an instant copy mechanism for each of the sets based on the type of mapping used to map the extents in each set.

4. The method of claim 1, wherein the mapping of the data is one of load point and offset and a full pointer mapping.

5. The method of claim 1, wherein the data is stored in a variable dynamically changeable mapping scheme storage area.

6. The method of claim 4, wherein performing an instant copy of the data using the instant copy operation includes using a full pointer table if the mapping of the data is a full pointer mapping.

7. The method of claim 4, wherein performing an instant copy of the data using the instant copy operation includes one of copying unchanged blocks of data from a source storage area to a new copy storage area and copying changed blocks of data from a source storage area to a new copy storage area.

8. The method of claim 2, further comprising generating copy meta-data based on the parsing of the extents of the data.

9. The method of claim 1, wherein the data is stored in an initial physical storage area, and wherein the instant copy operation includes copying a portion of the data from the initial physical storage area to an additional physical storage area in response to a data write to the location of the portion of data in the initial physical storage area.

10. The method of claim 9, wherein the instant copy operation further includes generating a pointer to a location, in the additional physical storage area, of the portion of data copied to the additional physical storage area.

11. The method of claim 1, wherein the data is stored in an initial physical storage area, and wherein if a data write occurs to a location of an additional physical storage area that is used to store copy data, the instant copy operation includes generating a pointer to the location in the additional physical storage area.

12. The method of claim 11, wherein if a data write occurs to the additional physical storage area, the portion of data referenced by the data write is not copied from the initial physical storage area to the additional physical storage area.

13. The method of claim 10, wherein the pointer is generated in a pointer table of meta-data associated with the additional physical storage area.

14. The method of claim 11, wherein the pointer is generated in a pointer table of meta-data associated with the additional physical storage area.

15. The method of claim 9, further comprising writing a new portion of data to the location of the portion of data in the initial physical storage area, after copying the portion of data to the additional physical storage area.

16. The method of claim 10, wherein the portion of data has a size that is different with respect to other portions of data in the data.

17. The method of claim 16, further comprising storing the pointer and an associated size of the portion of data in a meta-data data structure.

18. The method of claim 1, wherein the data is stored in an initial physical storage area, and wherein if there is a data write to a location of a portion of the data in the initial physical storage area, the data write is performed on an additional physical storage area rather than the initial physical storage area.

19. The method of claim 18, wherein if there is a data write to a location of a portion of the data in additional physical storage area, the data write is performed on the additional physical storage area.

20. The method of claim 19, wherein the additional physical storage area contains a combination of new data for original data and new data for copy data.

21. The method of claim 20, further comprising generating pointers for new data written to the additional physical storage device by the data write.

22. The method of claim 21, wherein pointers to new data for original data are linked to one another and pointers to new data for copy data are linked to one another.

23. The method of claim 20, further comprising separating the original data from the copy data.

24. The method of claim 23, 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.

25. The method of claim 24, 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.

26. The method of claim 25, 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.

27. The method of claim 25, 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.

28. The method of claim 1, wherein performing an instant copy of the data using the instant copy operation includes using a pair of pointers representing a range of pointers to point to portions of the data that have not been changed by a data write operation.

29. The method of claim 28, wherein performing an instant copy of the data using the instant copy operation further includes using individual pointers to point to portions of data that have changed due to a data write operation.

30. The method of claim 29, wherein the pair of pointers and the individual pointers are stored in a pointer table associated with a physical storage area.

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

first instructions for determining a mapping of the data;

second instructions for determining an instant copy operation based on the mapping of the data; and

third instructions for performing an instant copy of the data using the instant copy operation.

32. The computer program product of claim 31, wherein the first instructions for determining a mapping of the data include instructions for parsing extents of the data into sets based on types of mapping used to map the extents.

33. The computer program product of claim 32, wherein the second instructions for determining an instant copy operation based on the mapping of the data include instructions for setting up an instant copy mechanism for each of the sets based on the type of mapping used to map the extents in each set.

34. The computer program product of claim 31, wherein the mapping of the data is one of load point and offset and a full pointer mapping.

35. The computer program product of claim 31, wherein the data is stored in a variable dynamically changeable mapping scheme storage area.

36. The computer program product of claim 34, wherein the third instructions for performing an instant copy of the data using the instant copy operation include instructions for using a full pointer table if the mapping of the data is a full pointer mapping.

37. The computer program product of claim 34, wherein the third instructions for performing an instant copy of the data using the instant copy operation include instructions for one of copying unchanged blocks of data from a source storage area to a new copy storage area and copying changed blocks of data from a source storage area to a new copy storage area.

38. The computer program product of claim 32, further comprising fourth instructions for generating copy metadata based on the parsing of the extents of the data.

39. The computer program product of claim 31, wherein the data is stored in an initial physical storage area, and wherein the third instructions include instructions for copying a portion of the data from the initial physical storage area to an additional physical storage area in response to a data write to the location of the portion of data in the initial physical storage area.

40. The computer program product of claim 39, wherein the third instructions further include instructions for generating a pointer to a location, in the additional physical storage area, of the portion of data copied to the additional physical storage area.

41. The computer program product of claim 31, wherein the data is stored in an initial physical storage area, and wherein the third instructions include instructions for generating a pointer to a location in an additional physical storage area that is used to store copy data, if a data write occurs to the location of the additional physical storage area.

42. The computer program product of claim 41, wherein if a data write occurs to the additional physical storage area, the portion of data referenced by the data write is not copied from the initial physical storage area to the additional physical storage area.

43. The computer program product of claim 40, wherein the pointer is generated in a pointer table of meta-data associated with the additional physical storage area.

44. The computer program product of claim 41, wherein the pointer is generated in a pointer table of meta-data associated with the additional physical storage area.

45. The computer program product of claim 39, further comprising fourth instructions for writing a new portion of data to the location of the portion of data in the initial physical storage area, after copying the portion of data to the additional physical storage area.

46. The computer program product of claim 40, wherein the portion of data has a size that is different with respect to other portions of data in the data.

47. The computer program product of claim 46, further comprising fourth instructions for storing the pointer and an associated size of the portion of data in a meta-data data structure.

48. The computer program product of claim 31, wherein the data is stored in an initial physical storage area, and wherein if there is a data write to a location of a portion of the data in the initial physical storage area, the data write is performed on an additional physical storage area rather than the initial physical storage area.

49. The computer program product of claim 48, wherein if there is a data write to a location of a portion of the data in additional physical storage area, the data write is performed on the additional physical storage area.

50. The computer program product of claim 49, wherein the additional physical storage area contains a combination of new data for original data and new data for copy data.

51. The computer program product of claim 50, further comprising fourth instructions for generating pointers for new data written to the additional physical storage device by the data write.

52. The computer program product of claim 51, wherein pointers to new data for original data are linked to one another and pointers to new data for copy data are linked to one another.

53. The computer program product of claim 50, further comprising fourth instructions for separating the original data from the copy data.

54. The computer program product of claim 53, wherein the fourth instructions for separating the original data from the copy data includes 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.

55. The computer program product of claim 54, further comprising 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.

56. The computer program product of claim 55, 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.

57. The computer program product of claim 55, 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.

58. The computer program product of claim 31, wherein the third instructions for performing an instant copy of the data using the instant copy operation include instructions for using a pair of pointers representing a range of pointers to point to portions of the data that have not been changed by a data write operation.

59. The computer program product of claim 58, wherein the third instructions for performing an instant copy of the data using the instant copy operation further include instructions for using individual pointers to point to portions of data that have changed due to a data write operation.

60. The computer program product of claim 59, wherein the pair of pointers and the individual pointers are stored in a pointer table associated with a physical storage area.

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

means for determining a mapping of the data;

means for determining an instant copy operation based on the mapping of the data; and

means for performing an instant copy of the data using the instant copy operation.