METHODS AND APPARATUS FOR ARCHIVING DIGITAL DATA

• US 20090132775A1
• Filed: 11/19/2007
• Published: 05/21/2009
• Est. Priority Date: 11/19/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: OTANI, Toshio, Murase, Atsushi
• Granted Patent: US 7,861,049 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 16/113 Details of archiving lifecycle management in storage systems G06F3/0649; backup systems G06F11/1446
• CPC Class Codes: G06F 16/137 Hash-based content-based indexing of textual data G06F16/31
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097

Abstract

Method and apparatus are disclosed to enable secure archiving and backup of data with reduced risk of data lost. Additionally, embodiments are provided which enable reduction of costs for CAS backup of archived files by use of low-cost tape storage devices rather than expensive hard drive devices.

Claims

1. A method for managing a backup of files stored on a storage system and archived on a content addressable storage (CAS) system and duplicated on a backup storage system, the method comprising:

for each archiving operation performing the operations;

copying the files for archiving from the storage system onto the CAS to generate archived files;

maintaining a write protect in the storage system until a backup operation in the CAS system has been performed, thereby preventing any modifications of the files;

once a backup operation has been performed in the CAS system so as to generate duplicate files, deleting the files from the storage system.

2. The method of claim 1, wherein the storage system comprises a network attached storage (NAS) and further comprising storing a stub in the NAS indicating the storage location in the CAS of the archived files.

3. The method of claim 1, further comprising upon receiving a read request for one of the files, determining whether a corresponding archived file exists in the CAS archiving storage and, if so, fetching the corresponding archived file from the CAS system;

otherwise, fetching a corresponding backup file from the backup system and storing a copy in the CAS to thereby generate a restored archived file, and thereafter providing the restored archived file.

4. The method of claim 1, further comprising moving the backup files to an offline storage system.

5. The method of claim 4, wherein moving the backup files to an offline storage system comprises copying the files onto a tape storage system.

6. The method of claim 4, wherein moving the backup files to an offline storage system comprises copying the files onto one of a virtual tape library or virtual disk library.

21. The method of claim 4, wherein moving the backup files to an offline storage system comprises copying the files onto an optical disk array.

7. A method of managing file storage in first and second sites, each site having a storage system and content addressable storage (CAS) system, comprising:

synchronizing files in the storage system of the first site with storage system of the second site;

when an archiving operation begins in the first site, performing the steps;

enabling write protect on files on storage system in the first site;

copying the files from the storage system in the first site onto the CAS system in the first site;

monitoring archiving operation in the second site and, upon completion of archiving operation in the second site deleting the files from the storage system in the first site.

8. The method of claim 7, wherein archiving operation in the second site comprises copying files from the storage system of the second site to the CAS system of the second site.

9. The method of claim 7, wherein the storage system comprises a network attached storage (NAS) and further comprising storing a stub in the NAS system of the first site, indicating the storage location of the archived files in the CAS system of the first site.

10. The method of claim 7, further comprising upon receiving a read request from the storage system of the first site for one of the files, determining whether a corresponding archived file exists in the CAS storage of the first site and, if so, fetching the corresponding archived file from the CAS system of the first site;

otherwise, fetching a corresponding backup file from the CAS system of the second site and storing a copy in the CAS system of the first site to thereby generate a restored archived file, and thereafter providing the restored archived file to the storage system of the first site.

11. A system for storage, archival and backup of files, comprising:

a network attached storage (NAS) system providing modifiable files to users;

a content addressable storage (CAS) system for storing archival copies of the files;

a tape storage device coupled to the CAS system and storing backup copies of the archival copies.

12. The system of claim 11, further comprising a mapping table providing mapping of storage locations of archived files in the CAS system and corresponding backup copies in the tape storage device.

13. The system of claim 11, further comprising a plurality of logical units defined by the CAS system, and wherein each of the logical unit is assigned an attribute of primary or secondary, and wherein only files stored in logical units having secondary attribute are copied onto the tape storage.

14. The system of claim 13, wherein the CAS system copies files for archival from the NAS system onto logical units having primary attributes, and then makes a duplicate from the logical units having primary attribute onto logical unit having secondary attribute.

15. The system of claim 11, further comprising a plurality of storage devices and a storage device attribute table, the storage device attribute table having entries for each of the storage devices, the entries comprising device ID, device size, primary/secondary attribute, and availability condition.

16. A method of managing storage, archival and backup of files, comprising:

providing a network attached storage (NAS) system that provides modifiable files to users;

coupling to the NAS a content addressable storage (CAS) system and storing archival copies of the files in the NAS system;

coupling to the CAS system a tape storage device and storing backup copies of the archival copies in the tape storage device.

17. The method of claim 16, further comprising:

storing a stub having storage location address in the CAS for each archived file.

18. The method of claim 17, further comprising defining a plurality of logical units and assigning a primary or secondary attribute to each of the logical units, and backing up onto the tape storage only files stored in logical units having an assigned secondary attribute.

19. The method of claim 18, further comprising maintaining attribute table having entries for each of the logical units, the entries comprising device ID, device size, primary/secondary attribute, and availability condition.

20. The method of claim 16, further comprising maintaining a mapping table providing mapping of storage locations of archival files in the CAS system and corresponding backup copies in the tape storage device.