METHODS AND APPARATUS TO BACKUP AND RESTORE DATA FOR VIRTUALIZED STORAGE AREA

• US 20080282047A1
• Filed: 05/08/2007
• Published: 11/13/2008
• Est. Priority Date: 05/08/2007
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Akira, Kaneda, Yasunori, ARAKAWA, Hiroshi
• Application Number:
  US11/746,028
• Publication Number:
  US 20080282047A1
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

Information about management of virtualization (i.e. mapping between physical area/data/objects and logical area/data/objects) is provided by a storage system to a backup appliance (or common computer) that performs backup and restore of data. The backup appliance uses the information to recognize the mapping and to perform backup and restore process based on the mapping. Therefore the backup appliance handles only physical (really existing) area/data/objects to perform backup and restore rather than virtual ones. This realizes reducing the amount of data to be transferred and backed up, thus the problems mentioned above are solved.

Claims

1. A method for managing a backup system coupled to a storage system, said storage system communicating with a plurality of host computers, the method comprising;

operating the storage system to provide thin provisioned volumes (TPV) to the host computers;

maintaining mapping information of physical volumes assigned to the thin provisioned volumes;

providing the mapping information to the backup storage system;

operating the backup system to perform backup of only physical volumes assigned to the thin provisioned volumes, according to the mapping information.

2. The method of claim 1, wherein the mapping information comprises mapping between physical area, physical data and physical objects to corresponding logical area, logical data, and logical objects, respectively.

3. The method of claim 2, further comprising storing the mapping information in the backup system and, upon initiating restore operation, restoring the physical volumes according to the mapping information.

4. The method of claim 3, further comprising upon initiating a restore operation, sending the mapping information from the backup system to the storage system and comparing the mapping information from the backup system to the mapping information from the storage system and:

if no discrepancies are found, proceeding with the restore process;

if discrepancies are found, determining whether they are only addition of new chunks to the mapping information from the backup system and, if so, proceeding with the restore process;

otherwise, aborting the restore process.

5. The method of claim 1, further comprising:

sending a backup notification from the backup system to the storage system to initiate backup process;

upon receiving the backup notification at the storage system, sending the mapping information to the backup storage system; and

,

upon receiving the mapping information, storing the mapping information in the backup storage system.

6. The method of claim 1, further comprising:

upon receiving a write request from one of the host computers to a target TPV, querying the mapping information to identify assigned chunk in the physical volume corresponding to the target TPV;

checking whether the target TPV is under a backup process and, if yes, assigning a new chunk to the target TPV and performing the write request on the new chunk;

otherwise, performing the write request on the assigned chunk.

7. The method of claim 1, wherein transfer of data for backup and restore operation between the backup system and the storage system if performed via a data transfer volume.

8. The method of claim 1, wherein the data transfer volume comprise a virtual volume.

9. The method of claim 1, further comprising:

maintaining a link table comprising link to multiple identical items according to deduplication procedure;

providing the link table to the backup storage system;

operating the backup system to perform backup of only single instance of multiple identical items identified in the link table.

10. The method of claim 9, further comprising:

storing the link table in the backup storage system;

upon initiation of restore operation, sending the link table from the backup system to the storage system; and

, restoring only single instance of multiple identical items identified in the link table.

11. The method of claim 1, further comprising:

maintaining snapshot information in the storage system, the snapshot information maintaining a log of data stored as base data and data stored as old data, so as to enable constructing a snapshot of data at given moment in time;

maintaining base data information in the storage system, the base data information maintaining a log of base data stored in physical volume as base data;

maintaining old data information in the storage system, the old data information maintaining a log of old data stored in physical volume as base data;

upon initiation of backup by the backup system, sending to the backup system the snapshot information, the base data information and the old data information;

operating the backup system to back up the base data and the old data according to the snapshot information, the base data information and the old data information.

12. The method of claim 1, further comprising:

upon initiating a restore operation;

the backup system writes the snapshot information, the base data information and the old data information to a transfer volume;

the storage system prepares storage space according to the snapshot information, the base data information and the old data information;

the backup system copies the base data and old data onto the transfer volume in sequence;

the storage system reads the base data and old data onto from the transfer volume and writes the base data and old data onto the prepared storage space is sequence.

13. A method for managing a backup system and a storage system coupled to at least one host computer and having a physical storage facility, comprising:

dividing the physical storage facility into a plurality of chunks;

defining a plurality of virtual storage volumes;

assigning virtual storage volumes to applications operating in the host computer;

allocating selected chunks to each virtual storage volume;

maintaining a mapping of the allocation of selected chunks to virtual storage volumes;

maintaining an index for each allocated chunk to indicate whether the allocated chunk is empty or has been written to;

upon backup request, performing back up only for chunks for which the index indicates that data has been written to.

14. The method of claim 13, further comprising:

upon initiating restore operation by the backup system, transmitting the index to the storage system.

15. The method of claim 14, further comprising:

upon initiating restore operation by the backup system, transmitting the mapping to the storage system.

16. The method of claim 15, further comprising:

comparing the mapping information from the backup system to the mapping information from the storage system and;

if no discrepancies are found, proceeding with the restore process;

if discrepancies are found, determining whether they are only addition of new chunks to the mapping information from the backup system and, if so, proceeding with the restore process;

otherwise, aborting the restore process.

17. The method of claim 13, further comprising:

establishing a transfer volume; and

,

wherein performing back up comprises operating the storage system to write chunks for which the index indicates that data has been written to onto the transfer volume and subsequently operating the backup system to copy the chunks for which the index indicates that data has been written to from the transfer volume onto a backup volume.

18. The method of claim 17, further comprising:

upon initiating a restore operation;

backup system stores the mapping information in the transfer volume;

storage system reads the mapping information from the transfer volume and prepare storage chunks according to the mapping information;

backup system writes backed up data for restoring onto the transfer volume; and

,

storage system copies the backed up data from the transfer volume onto the storage chunks.

19. A storage system coupled to at least one host computer, the storage system comprising:

a plurality of storage discs, each disk defining a plurality of physical chunks;

at least one disk controller operative to control assigned storage discs;

a thin provisioning module assigning virtual volumes to applications operating in the host computer, and assigning physical chunks to the virtual volumes as needed;

a mapping module maintaining mapping information of physical chunks assigned to the virtual volumes and maintaining an index for each physical chunk to indicate whether the chunk is empty or has been written to.

20. The storage system of claim 19, further comprising a backup module, the backup module responsive to, upon receiving a backup initiation notification from a backup system, transmit the mapping information to the backup system.