Computer file management and backup system

• US 5,664,186 A
• Filed: 05/08/1995
• Issued: 09/02/1997
• Est. Priority Date: 05/21/1992
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bennett, Robert Bradley, Nugent, Robert Michael, Showalter, James Michael
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Choules, Jack M.
• Application Number:
  US08/436,783
• Time in Patent Office: 848 Days
• Field of Search: 395/489, 395/620, 395/618, 395/619
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency

Abstract

A file management and backup system manages access to data objects such as records stored in a primary repository, and occasionally backs-up the data objects to a backup repository. A backup utility within the system, periodically or at the request of a user, makes a backup request to a file manager, and specifies the scope of the backup. In response, the file manager makes an entry in a "backup in progress" table indicating that the corresponding file space(s), directory(ies), file(s) and/or data object(s) are currently involved in a consistent backup procedure. Then, the backup utility commences the actual copying of the data within the backup scope to the backup repository with assistance from the file manager in accessing the data from the primary repository. If a request is made to update a file space, directory, file or data object within the backup scope once the entry is made in the backup in progress table, the file manager makes a "shadow" or copy of the file space, directory, file or data object for which update is requested. Then, the file manager updates the original file space, directory, file or data object, and uses the shadow copy for the backup procedure. After the backup is completed, the shadow copy is invalidated. If the update request is made during the backup procedure to a directory, file or data object which has already been backed-up, then a shadow copy is not necessary.

Claims

1. A method for managing files listed in a directory, said method comprising the following steps performed in whole or part by a digital computer:

receiving a backup request with scope of said directory, and in response, locking said directory, then setting an indicator for said directory and then unlocking said directory;

receiving a request to change a specified file, and in response, determining that said specified file is listed in said directory and said indicator is set for said directory, making a copy of said specified file, making said change either to said specified file or said copy thereof; and

after the unlocking step, copying to a backup repository said directory and files including said specified file or said copy thereof which has not been changed but excluding said specified file or said copy thereof which has been changed, and then resetting said indicator.

2. A method as set forth in claim 1 wherein, pursuant to said change request, no copy is made of the files for which change has not been requested.

3. A method as set forth in claim 1 further comprising the steps of making another, subsequent request to backup said directory, and in response, subsequently copying to said backup repository said specified file or copy thereof which was changed in place of said specified file or copy thereof which was not changed.

4. A method as set forth in claim 1 wherein said directory was created and used for accessing said specified file before said backup request was made.

5. A method as set forth in claim 1 wherein said copy of said specified file is made only if said indicator is set and said request to change said specified file occurs before said specified file has been copied to said backup repository.

6. A method as set forth in claim 1 further comprising the steps of:

receiving a request to delete one of said files; and

if said indicator is set when said request is made to delete said one file, making a copy of said directory, and copying to said backup repository said directory and said files including said one file, and deleting from said directory copy an entry for said one file.

7. A method as set forth in claim 1 wherein said lock is set for a minimum time required to set said indicator.

8. A method as set forth in claim 1 wherein the files are stored on disk before backup, and said backup repository is a magnetic tape.

9. A method as set forth in claim 1 further comprising the step of generating and storing a logical, hierarchical view comprising said directory, said files descending from said directory and records descending from said files.

10. A method as set forth in claim 1 wherein:

said directory lists a plurality of files, one of said files being stored on two different disks along with other files listed in other directories; and

said backup request does not encompass any of said other files.

11. A method as set forth in claim 1 wherein:

a disk stores said specified file and at least one other file which is not listed in said directory; and

said backup request does not encompass said other file.

12. A method as set forth in claim 1 further comprising the following step which is implemented after said specified file or said copy thereof has been changed:

erasing or invalidating said specified file or said copy thereof which has not been changed after said specified file or copy thereof which has not been changed is copied to said backup repository, whereby said specified file or said copy thereof which has been changed is then an only accessible representation of said specified file outside of said backup repository.

13. A method as set forth in claim 12 wherein said specified file or said copy thereof which has not been changed is erased or invalidated after all of said files are copied to said backup repository.

14. A method as set forth in claim 1 wherein if said indicator is set when said change request is made and said specified file has already been copied to said backup repository, further comprising the step of making said change to said specified file without making a copy of said specified file.

15. A method as set forth in claim 1 wherein said indicator is a single bit.

16. A computer system for managing files listed in a directory, said computer system comprising:

means for receiving a backup request with scope of said directory;

means, responsive to said request, for locking said directory, then setting an indicator for said directory and then unlocking said directory;

means for receiving a request to update a specified file;

means, responsive to the update request, for determining that said specified file is listed in said directory and said indicator is set for said directory, making a copy of said specified file and updating said specified file or copy thereof; and

means, active after said directory is unlocked, for copying to a backup repository said directory and said files including said specified file or said copy thereof which has not been changed but excluding said specified file or copy thereof which has been changed, and then resetting said indicator.

17. A system as set forth in claim 16 wherein, pursuant to said update request, no copy is made of the files for which update has not been requested.

18. A system as set forth in claim 16 wherein the copy making means makes said copy of said specified file only if said request to update said specified file occurs before said specified file has been copied to said backup repository.

19. A system as set forth in claim 16 wherein the locking and unlocking means locks said directory for a minimum time required to set said indicator.

20. A system as set forth in claim 16 further comprising means for erasing or invalidating said specified file or said copy thereof which has not been changed, after the other of said specified file or said copy thereof has been changed and said specified file or said copy thereof which has not been changed is copied to said backup repository, whereby said specified file or said copy thereof which has been changed is then an only accessible representation of said specified file outside of said backup repository.

21. A system as set forth in claim 16 wherein said indicator is a single bit.

22. A method as set forth in claim 16 wherein:

said directory lists a plurality of files, one of said files being stored on two different disks along with other files listed in other directories; and

said backup request does not encompass any of said other files.

23. A method as set forth in claim 16 wherein:

a disk stores said specified file and at least one other file which is not listed in said directory; and

said backup request does not encompass said other file.

24. A method as set forth in claim 16 wherein said directory was created and used for accessing said specified file before said backup request was made.