Data recovery techniques in storage systems

• US 20040163029A1
• Filed: 12/01/2003
• Published: 08/19/2004
• Est. Priority Date: 12/02/2002
• Status: Abandoned Application

• Current Assignee: Arkivio (Rocket Software Incorporated)
• Original Assignee: Arkivio (Rocket Software Incorporated)
• Inventors: Kawecki, Lewis, Le, Nam, Yakir, Rony, Foley, Matthew J.
• Application Number:
  US10/726,007
• Publication Number:
  US 20040163029A1
• Time in Patent Office: Days
• US Class Current: 714/769
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency

Abstract

Techniques for maintaining data consistency in a storage environment. In a HSM controlled storage environment, techniques are provided for automatically detecting and correcting inconsistencies after a file system or a portion thereof has been restored from backup. The file system may store data files, tag files, and/or repository files that have been restored from backup.

Claims

1. In a storage environment comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer-implemented method of maintaining consistency of the file system of the first server, the method comprising:

providing first information comprising information related to the plurality of files stored in the file system of the first server, the first information comprising a plurality of entries, each entry corresponding to a file and storing status information identifying whether the file is a tag file or a data file, each entry storing attributes information identifying one or more attributes of the file;

comparing the plurality of files to information included in the first information;

identifying, based upon the comparing, at least a first inconsistency where information associated with a first file from the plurality of files is inconsistent with information in the first information; and

performing a first set of one or more operations to resolve the first inconsistency.

2. The method of claim 1 further comprising:

identifying at least a first entry in the first information that stores status information identifying a file as a tag file and for which there is no corresponding tag file in the plurality of files; and

performing a second set of one or more operations for the first entry.

3. The method of claim 2 wherein performing the second set of one or more operations comprises:

determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

deleting the first entry from the first information upon determining that a repository file corresponding to the first entry does not exist.

4. The method of claim 2 wherein performing the second set of one or more operations comprises:

determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

creating a tag file using information in the first entry upon determining that a repository file corresponding to the first entry exists.

5. The method of claim 2 wherein the plurality of files comprises one or more repository files storing migrated data, the method further comprising:

providing second information including information related to files stored by the plurality of servers that have been migrated;

comparing the one or more repository files to information stored in the first information and the second information;

identifying at least one inconsistency based upon comparing the one or more repository files to information in the first information and the second information; and

performing a set of one or more actions to resolve the at least one inconsistency.

6. The method of claim 1 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

identifying at least a first inconsistency comprises determining that the first information does not include an entry for the first file; and

performing the first set of one or more operations comprises deleting the first file.

7. The method of claim 1 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

identifying at least a first inconsistency comprises determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a data file; and

performing the first set of one or more operations comprises;

deleting the first file; and

deleting the entry in the first information corresponding to the first file.

8. The method of claim 1 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

identifying at least a first inconsistency comprises determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a tag file, wherein the attributes information stored by the entry does not match at least one attribute of the first file; and

performing the first set of one or more operations comprises updating the first file such that the at least one attribute of the first file matches the attributes information stored in the entry in the first information corresponding to the first file.

9. The method of claim 1 wherein:

the first file is a data file;

identifying at least a first inconsistency comprises determining that the first information does not include an entry for the first file; and

performing a first set of one or more operations comprises adding an entry to the first information for the first file.

10. The method of claim 1 wherein:

the first file is a data file;

identifying at least a first inconsistency comprises determining that the first information includes a first entry corresponding to the first file storing status information that identifies the file as a tag file; and

performing the first set of one or more operations comprises;

adding a second entry to the first information for the first file; and

creating a tag file to corresponding to the information in the first entry in the first information.

11. The method of claim 1 wherein:

the first file is a data file;

identifying at least a first inconsistency comprises determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a data file, wherein the attributes information stored by the entry does not match at least one attribute of the first file; and

performing the first set of one or more operations comprises updating the information in the first information entry corresponding first file such that the attributes information stored in the entry matches the at least one attribute of the first file.

12. In a storage environment comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer-implemented method of maintaining consistency of the file system of the first server, the method comprising:

providing first information including information related to files stored in the file system of the first server;

providing second information comprising a plurality of entries, each entry storing information related a file stored by the plurality of servers that has been migrated;

comparing a first tag file from the plurality of files to information stored in the second information;

identifying, based upon the comparing, at least a first inconsistency where information associated with the first tag file is inconsistent with the information included in the second information; and

performing a first set of one or more actions to resolve the first inconsistency.

13. The method of claim 12 wherein:

identifying the first inconsistency comprises determining that the second information does not include an entry for the first tag file; and

performing the first set of one or more actions comprises deleting the first tag file.

14. The method of claim 12 wherein:

identifying the first inconsistency comprises determining that the second information includes a first entry for the first tag file, a repository file exists for the first tag file, and information in the first entry does not match at least one attribute of the first tag file; and

performing the first set of one or more actions comprises;

updating the first tag file such that the at least one attribute of the first tag file matches the information in the first entry; and

adding an entry to the first information for the first tag file, the entry storing information related to the first tag file.

15. The method of claim 12 wherein:

identifying the first inconsistency comprises determining that the second information includes a first entry for the first tag file, a repository file exists for the first tag file, and information in the first entry matches one or more attributes of the first tag file; and

performing the first set of one or more actions comprises adding an entry to the first information for the first tag file, the entry storing information related to the first tag file.

16. The method of claim 12 further comprising:

identifying at least a first entry in the second information for which there is no corresponding tag file in the plurality of files; and

performing a second set of one or more operations for the first entry.

17. The method of claim 16 wherein performing the second set of one or more operations comprises:

determining, based upon information in the first entry in the second information, if a repository file exists corresponding to the first entry; and

deleting the first entry from the second information upon determining that a repository file corresponding to the first entry does not exist.

18. The method of claim 16 wherein performing the second set of one or more operations comprises:

determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

creating a tag file using information in the first entry for the second information upon determining that a repository file corresponding to the first entry exists.

19. In a storage environment managed by a hierarchical storage management application comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer-implemented method of recovering information, the method comprising:

providing first information including information related to one or more data files that have been migrated, wherein the information related to each data file that has been migrated includes information identifying a server and a volume from which the data file is migrated, and information identifying a server and volume where the migrated data of the data file is stored, the first information comprising information related to a first data file that has been migrated;

determining, based upon the first information, that the file system does not contain a tag file corresponding to first data file; and

creating a tag file corresponding to the first data file based upon information included in the first information.

20. In a storage environment comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer program product stored on a computer-readable medium for maintaining consistency of the file system of the first server, the computer program product comprising:

code for providing first information comprising information related to the plurality of files stored in the file system of the first server, the first information comprising a plurality of entries, each entry corresponding to a file and storing status information identifying whether the file is a tag file or a data file, each entry storing attributes information identifying one or more attributes of the file;

code for comparing the plurality of files to information included in the first information;

code for identifying, based upon the comparison, at least a first inconsistency where information associated with a first file from the plurality of files is inconsistent with information in the first information; and

code for performing a first set of one or more operations to resolve the first inconsistency.

21. The computer program product of claim 20 further comprising:

code for identifying at least a first entry in the first information that stores status information identifying a file as a tag file and for which there is no corresponding tag file in the plurality of files; and

code for performing a second set of one or more operations for the first entry.

22. The computer program product of claim 21 wherein the code for performing the second set of one or more operations comprises:

code for determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

code for deleting the first entry from the first information upon determining that a repository file corresponding to the first entry does not exist.

23. The computer program product of claim 21 wherein the code for performing the second set of one or more operations comprises:

code for determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

code for creating a tag file using information in the first entry upon determining that a repository file corresponding to the first entry exists.

24. The computer program product of claim 21 wherein the plurality of files comprises one or more repository files storing migrated data, the computer program product further comprising:

code for providing second information including information related to files stored by the plurality of servers that have been migrated;

code for comparing the one or more repository files to information stored in the first information and the second information;

code for identifying at least one inconsistency based upon comparing the one or more repository files to information in the first information and the second information; and

code for performing a set of one or more actions to resolve the at least one inconsistency.

25. The computer program product of claim 20 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

the code for identifying at least a first inconsistency comprises code for determining that the first information does not include an entry for the first file; and

the code for performing the first set of one or more operations comprises code for deleting the first file.

26. The computer program product of claim 20 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

the code for identifying at least a first inconsistency comprises code for determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a data file; and

the code for performing the first set of one or more operations comprises;

code for deleting the first file; and

code for deleting the entry in the first information corresponding to the first file.

27. The computer program product of claim 20 wherein:

the first file is a tag file representing a data file that has been migrated from the file system of the first server;

the code for identifying at least a first inconsistency comprises code for determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a tag file, wherein the attributes information stored by the entry does not match at least one attribute of the first file; and

the code for performing the first set of one or more operations comprises code for updating the first file such that the at least one attribute of the first file matches the attributes information stored in the entry in the first information corresponding to the first file.

28. The computer program product of claim 20 wherein:

the first file is a data file;

the code for identifying at least a first inconsistency comprises code for determining that the first information does not include an entry for the first file; and

the code for performing a first set of one or more operations comprises code for adding an entry to the first information for the first file.

29. The computer program product of claim 20 wherein:

the first file is a data file;

the code for identifying at least a first inconsistency comprises code for determining that the first information includes a first entry corresponding to the first file storing status information that identifies the file as a tag file; and

the code for performing the first set of one or more operations comprises;

code for adding a second entry to the first information for the first file; and

code for creating a tag file to corresponding to the information in the first entry in the first information.

30. The computer program product of claim 20 wherein:

the first file is a data file;

the code for identifying at least a first inconsistency comprises code for determining that the first information includes an entry corresponding to the first file storing status information that identifies the file as a data file, wherein the attributes information stored by the entry does not match at least one attribute of the first file; and

the code for performing the first set of one or more operations comprises code for updating the information in the first information entry corresponding first file such that the attributes information stored in the entry matches the at least one attribute of the first file.

31. In a storage environment comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer program product stored on a computer-readable medium for maintaining consistency of the file system of the first server, the computer program product comprising:

code for providing first information including information related to files stored in the file system of the first server;

code for providing second information comprising a plurality of entries, each entry storing information related a file stored by the plurality of servers that has been migrated;

code for comparing a first tag file from the plurality of files to information stored in the second information;

code for identifying, based upon the comparing, at least a first inconsistency where information associated with the first tag file is inconsistent with the information included in the second information; and

code for performing a first set of one or more actions to resolve the first inconsistency.

32. The computer program product of claim 31 wherein:

the code for identifying the first inconsistency comprises code for determining that the second information does not include an entry for the first tag file; and

code for performing the first set of one or more actions comprises code for deleting the first tag file.

33. The computer program product of claim 31 wherein:

the code for identifying the first inconsistency comprises code for determining that the second information includes a first entry for the first tag file, a repository file exists for the first tag file, and information in the first entry does not match at least one attribute of the first tag file; and

the code for performing the first set of one or more actions comprises;

code for updating the first tag file such that the at least one attribute of the first tag file matches the information in the first entry; and

code for adding an entry to the first information for the first tag file, the entry storing information related to the first tag file.

34. The computer program product of claim 31 wherein:

the code for identifying the first inconsistency comprises code for determining that the second information includes a first entry for the first tag file, a repository file exists for the first tag file, and information in the first entry matches one or more attributes of the first tag file; and

the code for performing the first set of one or more actions comprises code for adding an entry to the first information for the first tag file, the entry storing information related to the first tag file.

35. The computer program product of claim 31 further comprising:

code for identifying at least a first entry in the second information for which there is no corresponding tag file in the plurality of files; and

code for performing a second set of one or more operations for the first entry.

36. The computer program product of claim 35 wherein the code for performing the second set of one or more operations comprises:

code for determining, based upon information in the first entry in the second information, if a repository file exists corresponding to the first entry; and

code for deleting the first entry from the second information upon determining that a repository file corresponding to the first entry does not exist.

37. The computer program product of claim 35 wherein the code for performing the second set of one or more operations comprises:

code for determining, based upon information in the first entry, if a repository file exists corresponding to the first entry; and

code for creating a tag file using information in the first entry for the second information upon determining that a repository file corresponding to the first entry exists.

38. In a hierarchical storage management environment comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a computer program product stored on a computer-readable medium for recovering information, the computer program product comprising:

code for providing first information including information related to one or more data files that have been migrated, wherein the information related to each data file that has been migrated includes information identifying a server and a volume from which the data file is migrated, and information identifying a server and volume where the migrated data of the data file is stored, the first information comprising information related to a first data file that has been migrated;

code for determining, based upon the first information, that the file system does not contain a tag file corresponding to first data file; and

code for creating a tag file corresponding to the first data file based upon information included in the first information.

39. A storage system managed using a hierarchical storage management application, the storage system comprising:

a first server; and

a set of one or more storage units coupled to the first server, the set of storage units storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the set of storage units;

a memory configured to store first information comprising information related to the plurality of files stored on the set of storage units, the first information comprising a plurality of entries, each entry corresponding to a file, each entry storing status information identifying whether the file is a tag file or a data file, each entry storing attributes information identifying one or more attributes of the file;

wherein the first server is configured to

compare the plurality of files to information included in the first information,

identify, based upon the comparison, at least a first inconsistency where information associated with a first file from the plurality of files is inconsistent with information in the first information, and

perform a first set of one or more operations to resolve the first inconsistency.

40. A storage system managed using a hierarchical storage management application, the storage system comprising:

a first server; and

a set of one or more storage units coupled to the first server, the set of storage units storing a plurality of files restored from a backup medium, the plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the set of storage units; and

a memory configured to store first information and second information, the first information including information related to files stored by the set of storage units, the second information storing information for one or more files stored by the set of storage units that have been migrated;

wherein the first server is configured to

compare a first tag file from the plurality of files to information stored in the second information,

identify, based upon the comparing, at least a first inconsistency where information associated with the first tag file is inconsistent with the information included in the second information, and

perform a first set of one or more actions to resolve the first inconsistency.

41. In a storage system managed by a hierarchical storage management application, the storage system comprising a plurality of servers, the plurality of servers including a first server having a file system storing a plurality of files including one or more data files and one or more tag files corresponding to data files that have migrated from the file system, a data processing system comprising:

a processor; and

a memory configured to store first information including information related to one or more data files that have been migrated, wherein the information related to each data file that has been migrated includes information identifying a server and a volume from which the data file is migrated, and information identifying a server and volume where the migrated data of the data file is stored, the first information comprising information related to a first data file that has been migrated, the memory further configured to store a plurality of instructions which when executed by the processor cause the processor to;

determine, based upon the first information, that the file system does not contain a tag file corresponding to first data file; and

create a tag file corresponding to the first data file based upon information included in the first information.