SYSTEM AND METHOD FOR SYSTEM STATE REPLICATION

• US 20090222498A1
• Filed: 02/29/2008
• Published: 09/03/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Carbonite LLC (Open Text Corporation)
• Original Assignee: Double-Take Software Incorporated (Open Text Corporation)
• Inventors: LU, Xiaofeng, Demlow, David J., Beeler, Rob
• Granted Patent: US 8,001,079 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

The invention generally describes a system and method for data backup and recovery, in particular for backing up an entire server (i.e., system state and data) in substantially real-time. The invention provides high availability by failing a source server over to a target server if the source server fails, where the target server is reconfigured nearly identically to the source server. The invention does not require the source and target servers to have identical hardware or operating system versions. The invention further allows for rapid, automatic, restoration of a source server.

Claims

1. A method for backing up a first server, comprising the steps of:

replicating changes to data files and system state files of the first server to a second server;

detecting a failure of the first server; and

upon detection of the failure of the first server, failing over the first server to the second server by merging the replicated system state files of the first server into a system state of the second server.

2. The method of claim 1, further comprising an initial step of copying the data files and system state files of the first server to the second server.

3. The method of claim 1, where the step of replicating changes is performed asynchronously.

4. The method of claim 1, where replicated changes to a file of the first server are made to a corresponding copy of the file on the second server, copies of the system state files being located in a staging area on local storage of the second server.

5. The method of claim 1, where the step of merging the replicated system state files from the first server into a system state of the second server further comprises the steps of:

merging a registry of the second server with a registry of the first server and saving the merged registry to a file in a temporary storage area on the second server;

copying a non-conflicting subset of the replicated system state files of the first server to the temporary storage area, where the non-conflicting subset is constructed so as to retain hardware-dependent configuration of the second server; and

moving the system state files from the temporary storage area so as to overwrite corresponding system state files on the second server.

6. The method of claim 5, where the step of merging the replicated system state files from the first server into a system state of the second server further comprises the final step of rebooting the second server.

7. The method of claim 4, further comprising, after failover and restart of the first server, resynchronizing the data files of the second server to the first server.

8. The method of claim 7, further comprising the steps of:

after resynchronizing the data files of the second server to the first server, copying the system state files from the staging area on the second server to the first server; and

merging the copied system state files into a system state of the first server.

9. The method of claim 1, further comprising the step of replicating file changes to system state files of the second server to the first server, where replicated file changes are made to a corresponding copy of the file on the first server, copies of the system state files being located in a staging area on local storage of the first server.

10. The method of claim 9, further comprising, after failover and restart of the first server, merging the replicated system state files of the second server into a system state of the first server.

11. The method of claim 9, further comprising the steps of:

detecting a failure of the second server;

after restart of the second server, copying the system state files from the staging area of the first server to the second server; and

merging the copied system state files into a system state of the second server.

12. The method of claim 1, where the first server includes a plurality of source servers.

13. The method of claim 1, where the second server includes a plurality of target servers.

14. The method of claim 1, further comprising capturing image snapshots of the files on the first server at a plurality of times, and, upon detection of a failure at the first server, giving a user an option to restore the second server to any one of said captured image snapshots.

15. A method for backing up a first server comprising the steps of:

replicating changes to data files and system state files of the first server to a second server;

detecting a failure of the first server; and

upon detection of the failure of the first server, failing over the first server to a third server by the steps of;

copying the replicated data files of the first server from the second server to the third server;

copying the replicated system state files of the first server from the second server to the third server, where the replicated system state files of the first server are copied to a staging area on the third server; and

merging the copied system state files into a system state of the third server.

16. The method of claim 15, where the step of replicating changes is performed asynchronously.

17. The method of claim 15, where replicated changes to a file of the first server are made to a corresponding copy of the file on the second server, copies of the system state files being located in a staging area on local storage of the second server.

18. The method of claim 15, where the step of failing over the first server to a third server further comprises selecting the third server from a list of servers, where the list is stored on the second server.

19. The method of claim 15, where the method of failing over the first server to a third server further comprises, prior to copying the replicated system state files of the first server from the second server to the third server, validating the system state of the third server for compatibility with a system state of the first server.

20. The method of claim 15, further comprising an initial step of copying the data files and system state files of the first server to the second server.

21. The method of claim 17, further comprising, after failover and restart of the first server, resynchronizing the data files of the third server to the first server.

22. The method of claim 21, further comprising the steps of:

after resynchronizing the data files of the third server to the first server, copying the system state files from the staging area on the second server to the first server; and

merging the copied system state files into a system state of the first server.

23. The method of claim 21, further comprising the steps of:

after resynchronizing the data files of the third server to the first server, copying the system state files from the staging area on the third server to the first server; and

merging the copied system state files into a system state of the first server.

24. The method of claim 15, further comprising capturing image snapshots of the files on the first server at a plurality of times, and, upon detection of a failure at the first server, giving a user an option to restore the data files of said third server to reflect any one of said captured image snapshots.

25. A system for backup of a source server, comprising:

the source server, further including local storage and a connection to a network;

a target server, including local storage and a connection to the network;

a replication component executing on the source and target servers, where the replication component replicates changes to data files and system state files of the source server to the target server; and

a failover component executing on the source and target servers, where the failover component on the target server;

detects a failure of the source server, and

upon detection of the failure of the source server, fails over the source server to the target server by merging the replicated system state files of the source server into a system state of the target server.

26. The system of claim 25, wherein the replication component performs an initial step of copying the data files and system state files of the source server to the target server.

27. The system of claim 25, wherein the replication component replicates changes asynchronously.

28. The system of claim 25, wherein replicated changes to a file of the source server are made to a corresponding copy of the file on the target server, copies of the system state files being located in a staging area on the local storage of the target server.

29. The system of claim 25, wherein the step of merging the replicated system state files from the source server into a system state of the target server further comprises the steps of:

merging a registry of the target server with a registry of the source server and saving the merged registry to a file in a temporary storage area on the target server;

copying a non-conflicting subset of the replicated system state files of the source server to the temporary storage area, where the non-conflicting subset is constructed so as to retain hardware-dependent configuration of the target server; and

moving the files from the temporary storage area so as to overwrite corresponding system state files on the target server.

30. The system of claim 29, wherein the step of merging the replicated system state files from the source server into a system state of the target server further comprises the final step of rebooting the second server.

31. The system of claim 28, wherein the failover component further performs the step of, after failover and restart of the source server, resynchronizing the data files of the target server to the source server.

32. The system of claim 31, wherein the failover component further performs the steps of:

after resynchronizing the data files of the target server to the source server, copying the system state files from the staging area on the target server to the source server; and

merging the copied system state files into a system state of the source server.

33. The system of claim 25, wherein the replication component further performs the step of replicating file changes to system state files of the target server to the source server, where replicated file changes are made to a corresponding copy of the file on the source server, copies of the system state files being located in a staging area on the local storage of the target server.

34. The system of claim 33, wherein the failover component further performs the step of, after failover and restart of the source server, merging the replicated system state files of the target server into a system state of the source server.

35. The system of claim 33, wherein the failover component further performs the steps of:

detecting a failure of the target server;

after restart of the target server, copying the system state files from the staging area of the source server to the target server; and

merging the copied system state files into a system state of the target server.

36. The system of claim 25, wherein image snapshots of the files on the source server are captured by an image snapshot application operated by said image replication component, and wherein said failover component is configured to, upon detection of a failure at the source server, give a user an option to restore the target server to reflect any one of said captured image snapshots.

37. A system for backing up a source server comprising:

the source server, further including local storage and a connection to a network;

a backup server, including local storage and a connection to the network;

at least one target server, including local storage and a connection to the network;

a replication component executing on the source and backup servers, where the replication component replicates changes to data files and system state files of the source server to the backup server;

a failover component executing on the source, backup, and target servers, where the failover component on the backup server;

detects a failure of the source server, and

upon detection of the failure of the source server, fails over the source server to a selected target server from the at least one target servers by the steps of;

copying the replicated data files of the source server from the backup server to the selected target server;

copying the replicated system state files of the source server from the backup server to the selected target server, where the replicated system state files of the source server are copied to a staging area on the selected target server; and

merging the copied system state files into a system state of the selected target server.

38. The system of claim 37, wherein the replication component replicates changes asynchronously.

39. The system of claim 37, wherein replicated changes to a file of the source server are made to a corresponding copy of the file on the backup server, copies of the system state files being located in a staging area on the local storage of the backup server.

40. The system of claim 37, wherein the backup server selects the selected target server from a list of servers, where the list is stored on the backup server.

41. The system of claim 37, wherein the failover component further performs the step of, prior to copying the replicated system state files of the source server from the backup server to the selected target server, validating the system state of the selected target server for compatibility with a system state of the source server.

42. The system of claim 37, wherein the replication component further performs an initial step of copying the data files and system state files of the source server to the backup server.

43. The system of claim 39, wherein the failover component further performs the step of, after failover and restart of the source server, resynchronizing the data files of the selected target server to the source server.

44. The system of claim 43, wherein the failover component further performs the steps of:

after resynchronizing the data files of the selected target server to the source server, copying the system state files from the staging area on the backup server to the source server; and

merging the copied system state files into a system state of the source server.

45. The system of claim 43, wherein the failover component further performs the steps of:

after resynchronizing the data files of the selected target server to the source server, copying the system state files from the staging area on the selected target server to the source server; and

merging the copied system state files into a system state of the source server.

46. A computer-readable medium encoding a program for backing up a first server, where the program comprises a set of instructions for performing the steps of:

replicating changes to data files and system state files of the first server to a second server;

detecting a failure of the first server; and

upon detection of the failure of the first server, failing over the first server to the second server by merging the replicated system state files of the first server into a system state of the second server.

47. The computer-readable medium of claim 46, wherein the program further comprises instructions for performing an initial step of copying the data files and system state files of the first server to the second server.

48. The computer-readable medium of claim 46, wherein the step of replicating changes is performed asynchronously.

49. The computer-readable medium of claim 46, wherein replicated changes to a file of the first server are made to a corresponding copy of the file on the second server, copies of the system state files being located in a staging area on local storage of the second server.

50. The computer-readable medium of claim 46, wherein the step of merging the copied system state files from the first server into the system state of the second server further comprises the steps of:

merging a registry of the second server with a registry of the first server and saving the merged registry to a file in a temporary storage area on the second server;

copying a non-conflicting subset of the replicated system state files of the first server to the temporary storage area, where the non-conflicting subset is constructed so as to retain hardware-dependent configuration of the second server; and

moving the system state files from the temporary storage area so as to overwrite corresponding system state files on the second server.

51. The computer-readable medium of claim 50, wherein the step of merging the copied system state files from the first server into the system state of the second server further comprises the final step of rebooting the second server.

52. The computer-readable medium of claim 46, wherein the program further comprises instructions for performing the step of, after failover and restart of the first server, resynchronizing the data files of the second server to the first server.

53. The computer-readable medium of claim 52, wherein the program further comprises instructions for performing the steps of:

after resynchronizing the data files of the second server to the first server, copying the system state files from the staging area on the second server to the first server; and

merging the copied system state files into a system state of the first server.

54. The computer-readable medium of claim 46, wherein the program further comprises instructions for performing the step of replicating file changes to system state files of the second server to the first server, where replicated file changes are made to a corresponding copy of the file on the first server, copies of the system state files being located in a staging area on local storage of the first server.

55. The computer-readable medium of claim 54, wherein the program further comprises instructions for performing the step of, after failover and restart of the first server, merging the replicated system state files of the second server into a system state of the first server.

56. The computer-readable medium of claim 54, wherein the program further comprises instructions for performing the steps of:

detecting a failure of the second server;

after restart of the second server, copying the system state files from the staging area of the first server to the second server; and

merging the copied system state files into a system state of the second server.

57. The computer-readable medium of claim 46, wherein the first server is a plurality of source servers.

58. The computer-readable medium of claim 46, wherein the second server is a plurality of target servers.

59. A computer-readable medium encoding a program for backing up a first server, where the program comprises a set of instructions for performing the steps of:

replicating changes to data files and system state files of the first server to a second server;

detecting a failure of the first server; and

upon detection of the failure of the first server, failing over the first server to a third server by the steps of;

copying the replicated data files of the first server from the second server to the third server;

copying the replicated system state files of the first server from the second server to the third server, where the replicated system state files of the first server are copied to a staging area on the third server; and

merging the copied system state files into a system state of the third server.

60. The computer-readable medium of claim 59, wherein the step of replicating changes is performed asynchronously.

61. The computer-readable medium of claim 59, wherein replicated changes to a file of the first server are made to a corresponding copy of the file on the second server, copies of the system state files being located in a staging area on local storage of the second server.

62. The computer-readable medium of claim 59, wherein the step of failing over the first server to a third server further comprises selecting the third server from a list of servers, where the list is stored on the second server.

63. The computer-readable medium of claim 59, wherein the method of failing over the first server to a third server further comprises, prior to copying the replicated system state files of the first server from the second server to the third server, validating the system state of the third server for compatibility with a system state of the first server.

64. The computer-readable medium of claim 59, wherein the program further comprises instructions for performing an initial step of copying the data files and system state files of the first server to the second server.

65. The computer-readable medium of claim 61, wherein the program further comprises instructions for performing the step of, after failover and restart of the first server, resynchronizing the data files of the third server to the first server.

66. The computer-readable medium of claim 65, wherein the program further comprises instructions for performing the steps of:

after resynchronizing the data files of the third server to the first server, copying the system state files from the staging area on the second server to the first server; and

merging the copied system state files into a system state of the first server.

67. The computer-readable medium of claim 65, wherein the program further comprises instructions for performing the steps of:

after resynchronizing the data files of the third server to the first server, copying the system state files from the staging area on the third server to the first server; and

merging the copied system state files into a system state of the first server.