Method and system for synchronizing storage system data

• US 20070106852A1
• Filed: 12/21/2006
• Published: 05/10/2007
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: Ronald Niles, Wai Lam, Xiaowei Li
• Original Assignee: Ronald Niles, Wai Lam, Xiaowei Li
• Inventors: Lam, Wai, Li, Xiaowei, Niles, Ronald
• Granted Patent: US 7,590,808 B2
• Time in Patent Office: Days
• US Class Current: 711/154
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G06F 2221/2103 Challenge-response
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

In accordance with an example of an embodiment of the invention, a method for comparing a first unit of data stored in a first storage system and a second unit of data stored in a second storage system is provided. The method comprises generating a first digest that represents the first unit of data, generating an initial value associated with the first unit of data, and deriving an encoded value using the first digest and the initial value. The method further comprises transmitting the encoded value from the first storage system to the second storage system, generating a second digest that represents the second unit of data, and deriving a decoded value using the second digest to decode the encoded value. The method also comprises transmitting the decoded value from the second storage system to the first storage system, and determining whether the first unit of data and the second unit of data are duplicates of one another by comparing the decoded value and the initial value. Systems are also disclosed.

Claims

1. A method for comparing a first unit of data stored in a first storage system and a second unit of data stored in a second storage system, comprising:

generating a first digest that represents the first unit of data;

generating an initial value associated with the first unit of data;

deriving an encoded value using the first digest and the initial value;

transmitting the encoded value from the first storage system to the second storage system;

generating a second digest that represents the second unit of data;

deriving a decoded value using the second digest to decode the encoded value;

transmitting the decoded value from the second storage system to the first storage system; and

determining whether the first unit of data and the second unit of data are duplicates of one another by comparing the decoded value and the initial value.

2. The method of claim 1, wherein the first digest and the second digest are generated using a hash function.

3. The method of claim 2, wherein the hash function comprises a message digest 5 algorithm.

4. The method of claim 2, wherein the hash function comprises a secure hash algorithm.

5. The method of claim 1, wherein the first digest and the second digest are generated using a cyclic redundancy check.

6. The method of claim 1, wherein the first storage system and the second storage system communicate over a network.

7. The method of claim 6, wherein the network comprises an intranet.

8. The method of claim 6, wherein the network comprises a local area network.

9. The method of claim 6, wherein the network comprises a wide area network.

10. The method of claim 6, wherein the network comprises an internet.

11. The method of claim 6, wherein the network comprises a storage area network.

12. The method of claim 6, wherein the network comprises an Ethernet.

13. The method of claim 1, wherein the encoded value is transmitted in a command to decode the encoded value using the second digest that represents the second unit of data.

14. The method of claim 13, wherein the command is transmitted in accordance with SCSI protocols.

15. The method of claim 14, wherein the command comprises instructions contained in a SCSI command descriptor block.

16. The method of claim 1, wherein the initial value comprises a randomly-generated number.

17. A method for synchronizing a first unit of data stored in a first storage system and a second unit of data stored in a second storage system, comprising:

generating an first digest that represents the first unit of data;

generating an initial value associated with the first unit of data;

deriving an encoded value using the first digest and the initial value;

transmitting the encoded value from the first storage system to the second storage system;

generating a second digest that represents the second unit of data;

deriving a decoded value using the second digest to decode the encoded value;

transmitting the decoded value from the second storage system to the first storage system;

determining whether the first unit of data and the second unit of data are duplicates of one another by comparing the decoded value and the initial value; and

sending a copy of the first unit of data from the first storage system to the second storage system, and storing the copy in the second storage system, if the first unit of data is determined to be different from the second unit of data.

18. The method of claim 17, wherein the first digest and the second digest are generated using a hash function.

19. The method of claim 18, wherein the hash function comprises a message digest 5 algorithm.

20. The method of claim 18, wherein the hash function comprises a secure hash algorithm.

21. The method of claim 17, wherein the first digest and the second digest are generated using a cyclic redundancy check.

22. The method of claim 17, wherein the first storage system and the second storage system communicate over a network.

23. The method of claim 22, wherein the network comprises an intranet.

24. The method of claim 22, wherein the network comprises a local area network.

25. The method of claim 22, wherein the network comprises a wide area network.

26. The method of claim 22, wherein the network comprises an internet.

27. The method of claim 22, wherein the network comprises a storage area network.

28. The method of claim 22, wherein the network comprises an Ethernet.

29. The method of claim 17, wherein the encoded value is transmitted in a command to decode the encoded value using the second digest that represents the second unit of data.

30. The method of claim 29, wherein the command is transmitted in accordance with SCSI protocols.

31. The method of claim 30, wherein the command comprises instructions contained in a SCSI command descriptor block.

32. The method of claim 17, wherein the initial value comprises a randomly-generated number.

33. A system for comparing a first unit of data stored in a first storage system and a second unit of data stored in a second storage system, comprising:

a first controller configured to;

generate a first digest that represents the first unit of data;

generating an initial value associated with the first unit of data; and

derive an encoded value using the first digest and the initial value;

a first interface configured to;

transmit the encoded value from the first storage system to the second storage system;

a second controller configured to;

generate a second digest that represents the second unit of data; and

derive a decoded value using the second digest to decode the encoded value; and

a second interface configured to;

transmit the decoded value from the second storage system to the first storage system;

wherein, the first controller is further configured to;

determine whether the first unit of data and the second unit of data are duplicates of one another by comparing the decoded value and the initial value.

34. The system of claim 33, wherein the first digest and the second digest are generated using a hash function.

35. The system of claim 34, wherein the hash function comprises a message digest 5 algorithm.

36. The system of claim 34, wherein the hash function comprises a secure hash algorithm.

37. The system of claim 33, wherein the first digest and the second digest are generated using a cyclic redundancy check.

38. The system of claim 33, wherein the first storage system and the second storage system are configured to communicate over a network.

39. The system of claim 38, wherein the network comprises an intranet.

40. The system of claim 38, wherein the network comprises a local area network.

41. The system of claim 38, wherein the network comprises a wide area network.

42. The system of claim 38, wherein the network comprises an internet.

43. The system of claim 38, wherein the network comprises a storage area network.

44. The system of claim 38, wherein the network comprises an Ethernet.

45. The system of claim 33, wherein the first interface is further configured to:

transmit the encoded value in a command to decode the encoded value using the second digest that represents the second unit of data.

46. The system of claim 45, wherein the command is transmitted in accordance with SCSI protocols.

47. The system of claim 46, wherein the command comprises instructions contained in a SCSI command descriptor block.

48. The system of claim 33, wherein the initial value comprises a randomly-generated number.

49. A system for synchronizing a first unit of data stored in a first storage system and a second unit of data stored in a second storage system, comprising:

a first controller configured to;

generate a first digest that represents the first unit of data;

generate an initial value associated with the first unit of data; and

derive an encoded value using the first digest and the initial value;

a first interface configured to;

transmit the encoded value from the first storage system to the second storage system;

a second controller configured to;

generate a second digest that represents the second unit of data; and

derive a decoded value using the second digest to decode the encoded value; and

a second interface configured to;

transmit the decoded value from the second storage system to the first storage system;

wherein, the first controller is further configured to;

determine whether the first unit of data and the second unit of data are duplicates of one another by comparing the decoded value and the initial value; and

wherein, the first controller is further configured to;

send a copy of the first unit of data from the first storage system to the second storage system, the copy being stored in a memory in the second storage system, if the first unit of data is determined to be different from the second unit of data.

50. The system of claim 49, wherein the first digest and the second digest are generated using a hash function.

51. The system of claim 50, wherein the hash function comprises a message digest 5 algorithm.

52. The system of claim 50, wherein the hash function comprises a secure hash algorithm.

53. The system of claim 49, wherein the first digest and the second digest are generated using a cyclic redundancy check.

54. The system of claim 49, wherein the first storage system and the second storage system are configured to communicate over a network.

55. The system of claim 54, wherein the network comprises an intranet.

56. The system of claim 54, wherein the network comprises a local area network.

57. The system of claim 54, wherein the network comprises a wide area network.

58. The system of claim 54, wherein the network comprises an internet.

59. The system of claim 54, wherein the network comprises a storage area network.

60. The system of claim 54, wherein the network comprises an Ethernet.

61. The system of claim 49, wherein the first interface is further configured to:

transmit the encoded value in a command to decode the encoded value using the second digest that represents the second unit of data.

62. The system of claim 61, wherein the command is transmitted in accordance with SCSI protocols.

63. The system of claim 62, wherein the command comprises instructions contained in a SCSI command descriptor block.

64. The system of claim 49, wherein the initial value comprises a randomly-generated number.