Automated management of off-site storage volumes for disaster recovery

• US 5,673,382 A
• Filed: 05/30/1996
• Issued: 09/30/1997
• Est. Priority Date: 05/30/1996
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kaczmarski, Michael Allen, Cannon, David Maxwell
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Palys, Joseph E.
• Application Number:
  US08/655,791
• Time in Patent Office: 488 Days
• Field of Search: 395/182.04, 395/182.13, 395/182.17, 395/182.18, 395/618, 395/620, 395/622
• US Class Current: 714/6.31
• CPC Class Codes: G06F 11/1464 for networked environments

Abstract

A data processing system providing disaster recovery and using a client-server configuration provides a method and apparatus for reclaiming off-site storage volumes without requiring the volumes to be mounted or transported to the primary site. The system includes primary volumes and resident copy volumes at the primary site and off-site storage volumes for disaster recovery at the remote site. The system first determines which off-site storage volumes are eligible for reclamation. For each eligible off-site volume, the system locates, within the primary site, a primary copy of every file remaining on the off-site volume that is still required for disaster recovery. These primary copies are then copied to a resident recovery volume at the primary storage site. The eligible off-site volume is then marked empty, and the resident recovery volume is classified as an off-site volume. The resident recovery volume is then transported to the remote storage site and the empty off-site volume is returned to the primary storage site to be reused as a resident copy volume.

Claims

1. In a disaster recovery system having a primary storage site and a remote storage site, said remote storage site having a plurality of off-site storage volumes for storing a disaster recovery copy of client data files, said primary storage site having a plurality of client systems generating said client data files, and a server coupled to said plurality of client systems for managing copies of said client data files at said primary storage site and said remote storage site, said server comprising:

a plurality of primary storage volumes for storing a primary copy of said client data files;

a plurality of resident copy storage volumes for storing a back-up copy of said client data files;

a server database for maintaining directory information and reference location information for said copies of said client data files; and

a storage manager coupled to said primary storage volumes, said resident copy storage volumes, and said server database, said storage manager storing said primary copy of said client data file received from said client system in said primary storage volume, said storage manager also determining which of said resident copy storage volumes are to be classified as off-site storage volumes and transported to said remote storage site for disaster recovery, said storage manager also reclaiming said off-site storage volumes without mounting said off-site storage volumes at said primary storage site or said remote storage site.

2. The server in claim 1 further comprising:

a first list in said server database identifying a set of eligible off-site storage volumes to be reclaimed,

wherein said storage manager queries said directory information and said reference location information in said server database to build said first list.

3. The server in claim 2 further comprising:

a second list in said server database identifying a set of remaining disaster recovery copies stored on said eligible off-site storage volume, said set of remaining disaster recovery copies necessary for disaster recovery,

wherein said storage manager queries said directory information and said reference location information in said server database to build said second list.

4. The server in claim 3 wherein said storage manager copies said primary copy corresponding to said remaining back-up copy from said primary storage volume to a recovery resident copy storage volume.

5. The server in claim 4 wherein said storage manager classifies said eligible off-site storage volume as empty when said primary copies corresponding to all of said remaining disaster recovery copies have been copied to said recovery resident copy storage volume.

6. The server in claim 5 wherein said storage manager reuses said eligible off-site storage volume classified as empty once said eligible off-site storage volume is returned to said primary storage site, said eligible off-site storage volume returned only after said recovery resident copy storage volume is transported to said remote site.

7. The server in claim 3 further comprising:

a file space occupied by said set of remaining back-up copies in said eligible off-site storage volume,

wherein said storage manager calculates said file space from said reference location information in said server database, said storage manager further comparing said file space to a minimum threshold and determining that said eligible off-site volume can be reclaimed if said file space is less than said minimum threshold.

8. The server in claim 7 wherein said directory information in said server database for each said primary copy and each said back-up copy of said client data file further comprises:

a file name;

a client system identifier;

a file status word;

a time stamp; and

a bit-file identifier (bfid).

9. The server in claim 7 wherein said reference location information in said server database for each said primary copy and each said back-up copy of said client data file further comprises:

a storage pool identifier;

a storage volume identifier;

a storage volume offset;

a file size; and

a bit-file identifier (bfid).

10. The server in claim 1 wherein said primary storage volumes are direct access storage devices (DASDs).

11. The server in claim 1 wherein said primary storage volumes are magnetic tape cartridges.

12. The server in claim 1 wherein said copy storage volumes are magnetic tape cartridges.

13. In a disaster recovery system having a primary storage site and a remote storage site, said primary storage site having a plurality of client systems generating client data files, a server coupled to said plurality of client systems, said server having a plurality of primary storage volumes for storing a primary copy of said client data files and a plurality of resident copy storage volumes for storing a back-up copy of said client data files, said remote storage site having a plurality of off-site storage volumes for storing said back-up copies needed for disaster recovery, a method in said server for reclaiming said off-site storage volume without mounting said off-site storage volume comprising steps of:

maintaining directory information and reference location information in a server database to link said primary copy and said back-up copy of said client data files;

selecting a set of eligible off-site storage volumes to be reclaimed;

for each said eligible off-site storage volume, identifying a set of remaining back-up copies stored on said off-site storage volume necessary to maintain disaster recovery protection;

for each said remaining back-up copy, copying said primary copy corresponding to said remaining back-up copy from said primary storage volume to a recovery resident copy storage volume; and

classifying said recovery resident copy storage volume as a new off-site storage volume and said eligible off-site storage volume as empty.

14. The method of claim 13 further comprising:

reusing said eligible off-site volume as a resident copy storage volume once said eligible off-site volume is returned to said primary storage site, said eligible off-site volume returned to said primary storage site after said recovery resident copy storage volume transported to said remote storage site.

15. The method of claim 13 wherein said selecting step further comprises:

querying said directory information and said reference location information in said server database to identify said off-site storage volumes;

for each said off-site storage volume, calculating a useable space occupied by said remaining back-up copies;

comparing said useable space with a minimum threshold; and

categorizing said off-site storage volume as said eligible off-site storage volume if said useable space is less than said minimum threshold.

16. The method of claim 13 wherein said identifying step further comprises:

querying said directory information and said reference location information in said server database to locate said set of remaining back-up copies necessary for disaster recovery.

17. The method of claim 15 wherein said calculating step further comprises:

querying said reference location information in said server database to find a size of each said remaining back-up copy; and

adding said size of each said remaining back-up copy stored on said off-site storage volume to determine said useable space.

18. The method of claim 17 wherein said directory information in said server database for each said primary copy and each said back-up copy of said client data file further comprises:

a file name;

a client system identifier;

a file status word;

a time stamp; and

a bit-file identifier (bfid).

19. The method of claim 17 wherein said reference location information in said server database for each said primary copy and each said back-up copy of said client data file further comprises:

a storage pool identifier;

a storage volume identifier;

a storage volume offset;

a file size; and

a bit-file identifier (bfid).

20. In a disaster recovery system having a primary storage site and a remote storage site, said primary storage site having a plurality of client systems generating client data files, a server coupled to said plurality of client systems, said server having a plurality of primary storage volumes for storing a primary copy of said client data files and a plurality of resident copy storage volumes for storing a back-up copy of said client data files, said remote storage site having a plurality of off-site storage volumes for storing said back-up copies needed for disaster recovery, a program product having executable computer instructions for reclaiming said off-site storage volume without mounting said off-site storage volume comprising:

a computer readable storage medium for storing said executable computer instructions, said executable computer instructions comprising;

maintaining directory information and reference location information in a server database to link said primary copy and said back-up copy of said client data files;

selecting a set of eligible off-site storage volumes to be reclaimed;

for each said eligible off-site storage volume, identifying a set of remaining back-up copies stored on said off-site storage volume necessary to maintain disaster recovery protection;

for each said remaining back-up copy, copying said primary copy corresponding to said remaining back-up copy from said primary storage volume to a recovery resident copy storage volume; and

classifying said recovery resident copy storage volume as a new off-site storage volume and said eligible off-site storage volume as empty.