Method and apparatus for managing backup data

• US 20050193236A1
• Filed: 02/04/2005
• Published: 09/01/2005
• Est. Priority Date: 02/04/2004
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Alacritus, Inc. (NetApp, Inc.)
• Inventors: Chang, Yafen Peggy, Johnston, Craig Anthony, Trimmer, Donald Alvin, Stager, Roger Keith, Saxena, Pawan, Blaser, Rico
• Granted Patent: US 7,904,679 B2
• Time in Patent Office: Days
• US Class Current: 714/6.11
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 11/1461 Backup scheduling policy

Abstract

A method and apparatus for managing backup data is disclosed. A data backup system defines a plurality of time windows for creating and maintaining backup data in accordance with a data backup policy. Each of the time windows is assigned a predetermined amount of storage space. When the data backup system creates backup data, the system determines whether a storage space assigned to a time window is large enough to accommodate new backup data. If the storage space is large enough, the new backup data is stored. However, if the storage space is not large enough, the system deletes the oldest backup data until enough storage space is obtained.

Claims

1. A method for protecting backup data stored in a data backup system, the method comprising:

defining a plurality of time windows for creating and maintaining backup data in accordance with the data backup policy;

assigning each of the time windows a predetermined amount of storage space;

creating a backup data in accordance with a data backup policy;

determining whether a storage space assigned to a time window is enough for a new backup data; and

storing the new backup data if the storage space is enough, if not delete the oldest backup data until enough storage space in the assigned storage space is obtained.

2. The method of claim 1 further comprising a step of assigning each of the time windows a predetermined number for data backups, whereby new backup data is created and maintained as far as the assigned number has not reached.

3. The method of claim 2 further comprising a step of providing an internal clock for the data backup system independent from a main clock of a main system and setting an expiration time for each backup data, whereby the data backup system calculates the expiration time with the internal clock.

4. A method for protecting backup data stored in a data backup system, the backup data being created in accordance with a data backup policy, the method comprising:

defining a plurality of time windows for creating and maintaining backup data in accordance with the data backup policy;

assigning each of the time windows a predetermined number for data backup;

creating a backup data in a certain time window in accordance with a data backup policy;

determining whether the number of backup data in the time window is within the assigned number; and

storing the new backup data if the number of backup data in the time window is within the assigned number.

5. The method of claim 4 wherein if the number of backup data is not within the assigned number, the oldest backup data is deleted before storing the new backup data.

6. The method of claim 4 wherein if the number of backup data is not within the assigned number, generation of new backup data stops.

7. The method of claim 4 wherein if the number of backup data is not within the assigned number, interleaving backup data is deleted before storing the new backup data.

8. The method of claim 4 further comprising a step of providing an internal clock for the data backup system independent from a main clock of a main system and setting an expiration time for each backup data, whereby the data backup system calculates the expiration time with the internal clock.

9. A method for protecting backup data stored in a data backup system, the data backup system backing up data generated by a main system, the method comprising:

providing an internal clock for the data backup system independent from a main clock of the main system;

creating a plurality of backup data in accordance with a data backup policy, each backup data having an expiration time to be removed from the data backup system; and

removing the backup data in accordance with the internal clock regardless of the main clock.

10. The method of claim 9 wherein an interval during which the system is up is recorded and the internal clock is reset using the last recorded interval when the system is recovered from the shut down.

11. An apparatus for backing up data comprising:

a backup data generation unit for creating a backup data in accordance with a data backup policy;

a data storage for storing the backup data; and

a controller for defining a plurality of time windows for creating and maintaining backup data in accordance with the data backup policy, and for assigning each of the time windows a predetermined amount of storage space, whereby a new backup data created during a particular time window is stored in a storage space assigned to the time window if the assigned storage space has not been used up, and if the assigned storage space has been used up, deleting the oldest backup data until enough storage space in the assigned storage space is obtained.

12. The apparatus of claim 11 wherein the controller further assigns each of the time windows a predetermined number for data backups, whereby the new backup data is stored if the number of backup data in the time window is within the assigned number.

13. The apparatus of claim 12 wherein if the number of backup data is not within the assigned number, the oldest backup data is deleted before storing the new backup data.

14. The apparatus of claim 12 wherein if the number of backup data is not within the assigned number, generation of new backup data stops.

15. The apparatus of claim 12 wherein if the number of backup data is not within the assigned number, interleaving backup data is deleted before storing the new backup data.

16. The apparatus of claim 12 further comprising an internal clock independent from a main clock of a main system, whereby the controller maintains the backup data in accordance with the internal clock.

17. The apparatus of claim 11 wherein the backup data generation unit generates a snapshot of the data.

18. The apparatus of claim 17 wherein the snapshot is stored in a secondary storage.

19. An apparatus for backing up data comprising:

a backup data generation unit for creating a backup data in accordance with a data backup policy;

a data storage for storing the backup data; and

a controller for defining a plurality of time windows for creating and maintaining backup data in accordance with the data backup policy, and for assigning each of the time windows a predetermined number of data backups, whereby the controller maintains the number of backup data within the predetermined number during the corresponding time window.

20. The apparatus of claim 19 further comprising an internal clock independent from a main clock of a main system, whereby the controller maintains the backup data in accordance with the internal clock.

21. The apparatus of claim 19 wherein the backup data generation unit generates a snapshot of the data.

22. The apparatus of claim 21 wherein the snapshot is stored in a secondary storage.

23. An apparatus for backing up data comprising:

a backup data generation unit for creating a backup data for backing up data generated by a main system in accordance with a data backup policy, each backup data having an expiration time to be removed;

a data storage for storing the backup data;

an internal clock; and

a controller maintains the backup data in accordance with the internal clock independent from a main clock of the main system.

24. The apparatus of claim 23 wherein the backup data generation unit generates a snapshot of the data.

25. The apparatus of claim 24 wherein the snapshot is stored in a secondary storage.

26. The apparatus of claim 25 wherein an interval during which the system is up is recorded and the internal clock is reset using the last recorded interval when the system is recovered from the shut down.