Virtual data store creation and use

• US 7,991,748 B2
• Filed: 02/17/2004
• Issued: 08/02/2011
• Est. Priority Date: 09/23/2003
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Corporation (NortonLifeLock Inc.)
• Inventors: Rodgers, Kevin F., Rowan, Michael T.
• Primary Examiner(s): Kim; Paul
• Application Number:
  US10/780,004
• Publication Number:
  US 20050065962A1
• Time in Patent Office: 2,723 Days
• Field of Search: 711/136, 707/1, 707/677, 707/685, 707/686, 1/1
• US Class Current: 707/677
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 16/21 Design, administration or maintenance of databases

Abstract

A method, apparatus, and system for accessing units of storage that depends at least in part on an address of the unit of storage and the time that data was written to the unit of storage. A virtual data store can be created that reflects the state of an original data store at a specified time, where the specified time is selected, for example, from a substantially continuous time interval.

Claims

1. A method for providing data, the method comprising the steps of:

storing, in an original data store, details associated with all write commands directed to a primary data store during a time interval so as to accumulate backup data, each write command being stored when directed to the primary data store, wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

receiving a request to create a virtual data store that reflects a state of the primary data store at a specified time, the specified time being any point in time during the time interval that occurs prior to the creation of a snapshot of the primary data store;

creating the virtual data store from data stored in the original data store;

receiving a storage protocol request for data at a specified address in the virtual data store; and

transmitting the requested data in response to the storage protocol request.

2. The method of claim 1 wherein the original data store comprises another virtual data store.

3. The method of claim 2 wherein the original data store comprises a current store and a time store.

4. The method of claim 1 wherein the virtual data store comprises a logical unit.

5. The method of claim 4 wherein both the request to create the virtual data store and the storage protocol request are received in a single protocol request packet.

6. The method of claim 4 wherein the request to create the virtual data store is received in a different data packet than the storage protocol request.

7. The method of claim 1 wherein the request to create the virtual data store is received via a user interface.

8. The method of claim 1 wherein the request to create the virtual data store is received via the storage protocol request.

9. The method of claim 1 wherein the storage protocol request comprises a standard read request.

10. The method of claim 9 wherein the storage protocol request comprises a SCSI read request.

11. The method of claim 1 wherein the storage protocol request comprises a Fibre Channel protocol request.

12. The method of claim 1 wherein the storage protocol request is received over a Fibre Channel physical layer.

13. The method of claim 1 wherein the request to create the virtual data store is received from a host.

14. The method of claim 1 wherein the request to create the virtual data store is received from a network.

15. The method of claim 1 wherein the original data store comprises a current store and a time store.

16. The method of claim 1 wherein the virtual data store comprises a current store and a time store.

17. The method of claim 1 wherein the original data store comprises at least one terabyte of data.

18. The method of claim 17 wherein the original data store comprises multiple physical storage devices.

19. The method of claim 18 wherein the multiple physical storage devices comprise at least ten physical storage devices.

20. The method of claim 19 wherein the multiple physical storage devices comprise at least 100 physical storage devices.

21. The method of claim 1 wherein the virtual data store comprises a read only data store.

22. The method of claim 1 wherein the data is transmitted substantially instantaneously in response to the storage protocol request.

23. The method of claim 22 wherein the data is transmitted in less than 1 millisecond.

24. The method of claim 1, further comprising the step of writing data to the virtual data store in response to a storage protocol write request.

25. The method of claim 24 wherein the storage protocol write request comprises a standard write request.

26. The method of claim 25 wherein the storage protocol write request comprises a SCSI write request.

27. The method of claim 24 wherein the storage protocol write request comprises a Fibre Channel protocol request.

28. A method for providing data, the method comprising the steps of:

storing, in an original data store, details associated with all write commands directed to a primary data store during a time interval so as to accumulate backup data, each write command being stored when directed to the primary data store, wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

receiving a request to create a virtual data store;

generating, substantially instantaneously and from data stored in the original data store, the virtual data store that reflects the state of the primary data store at a specified time, the specified time being any point in time during the time interval that occurs prior to the creation of a snapshot of the primary data store;

receiving a storage protocol request for data at a specified address in the virtual data store; and

transmitting the requested data in response to the storage protocol request.

29. The method of claim 28, further comprising the step of copying the virtual data store to another data store.

30. The method of claim 29 wherein the other data store comprise a virtual data store.

31. The method of claim 28 wherein the original data store comprise a virtual data store.

32. The method of claim 31 wherein the original data store is implemented as a current store and a time store.

33. The method of claim 28 wherein the virtual data store comprises a logical unit.

34. The method of claim 28, further comprising, before the generating step, the step of receiving a request to create the virtual data store.

35. The method of claim 34 wherein the virtual data store is generated within one second of the request to create the virtual data store.

36. An article of manufacture having computer-readable program portions contained therein for providing data, the article comprising:

a computer-readable program portion for storing, in an original data store, details associated with all write commands directed to a primary data store during a time interval so as to accumulate backup data, each write command being stored when directed to the primary data store, wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

a computer-readable program portion for receiving a request to create a virtual data store that reflects a state of the primary data store at a specified time, the specified time being any point in time during the time interval that occurs prior to the creation of a snapshot of the primary data store;

a computer-readable program portion for creating the virtual data store from data stored in the original data store;

a computer-readable program portion for receiving a storage protocol request for data at a specified address in the virtual data store; and

a computer-readable program portion for transmitting the requested data in response to the storage protocol request.

37. A system for providing data, comprising:

an original data store that stores details associated with all write commands directed to a primary data store during a time interval so as to accumulate backup data, each write command being stored when directed to the primary data store, wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

a virtual data store that reflects a state of the primary data store at a specified time, the specified time being any point in time during the time interval that occurs prior to the creation of a snapshot of the primary data store;

a virtual data store generator that generates the virtual data store from data stored in the original data store;

a receiver that receives a storage protocol request for data at a specified address in the virtual data store; and

a transmitter that transmits the requested data in response to the storage protocol request.

38. The system of claim 37, further comprising a storage protocol write request.

39. The system of claim 38 wherein a standard I/O command comprises at least one of the storage protocol request and the storage protocol write request.

40. The system of claim 39 wherein the standard I/O command comprises a SCSI command.

41. The system of claim 40 wherein the standard I/O command comprises a Fibre Channel protocol request.

42. A method of receiving data from a data store, the method comprising the steps of:

selecting a specified time from any point in time during a time interval that occurs prior to the creation of a snapshot of a first logical unit;

communicating to a storage device a request to create a virtual logical unit that reflects a state of the first logical unit at the specified time, wherein backup data associated with the first logical unit have been accumulated by storing details associated with all write commands directed to the first logical unit during the time interval, wherein each write command is stored when directed to the primary data store, and wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

creating the virtual logical unit from the backup data and the first logical unit;

communicating to the storage device a storage protocol request for data in the virtual logical unit; and

receiving a response comprising the requested data as the data appeared in the first logical unit at the specified time.

43. The method of claim 42 wherein the step of receiving a response further comprises receiving a substantially instantaneous response to the storage protocol request.

44. The method of claim 43 wherein the first logical unit comprises at least one terabyte of data.

45. The method of claim 43 wherein the response is received in less than 1 millisecond.

46. An article of manufacture having computer-readable program portions contained therein for receiving data from a data store, the article comprising:

a computer-readable program portion for selecting a specified time from any point in time during a time interval that occurs prior to the creation of a snapshot of a first logical unit;

a computer-readable program portion for communicating to a storage device a request to create a virtual logical unit that reflects a state of the first logical unit at the specified time, wherein backup data associated with the first logical unit have been accumulated by storing details associated with all write commands directed to the first logical unit during the time interval, wherein each write command is stored when directed to the primary data store, and wherein the details associated with all write commands comprise an overwrite timestamp parameter, a primary data store location parameter, an original data store location parameter, and an overwritten data parameter;

a computer-readable program portion for creating the virtual logical unit from the backup data and the first logical unit;

a computer-readable program portion for communicating to the storage device a storage protocol request for data in the virtual logical unit; and

a computer-readable program portion for receiving a response comprising the requested data as the data appeared in the first logical unit at the specified time.