Transforming unrelated data volumes into related data volumes

• US 7,664,793 B1
• Filed: 07/01/2003
• Issued: 02/16/2010
• Est. Priority Date: 07/01/2003
• Status: Expired due to Fees

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (NortonLifeLock Inc.)
• Inventors: Pendharkar, Niranjan S., Kiselev, Oleg, Colgrove, John A., Karr, Ronald S., Kekre, Anand A.
• Primary Examiner(s): Vo; Tim T.
• Assistant Examiner(s): Dwivedi; Mahesh H
• Application Number:
  US10/610,961
• Time in Patent Office: 2,422 Days
• Field of Search: 707/201, 707/204, 711/162
• US Class Current: 707/811
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1466 to make the backup process non-disruptive
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008

Abstract

Disclosed is an apparatus and method for transforming unrelated data volumes into related data volumes. The present invention is employed after creation of first and second unrelated data volumes. In one embodiment, the second data volume is refreshed to the data contents of the first data volume so that the second data becomes a PIT copy of the first data volume. Refreshing the second data volume includes overwriting all data of the second data volume with data copied from the first data volume. However, before all data of the second data volume is overwritten with data copied from the first data volume, data of the first data volume can be modified.

Claims

1. A method comprising:

writing first and second data to first and second data volumes, respectively, wherein

the first data volume is a first primary volume,

the second data volume is a second primary volume, and

the first and second data volumes are unrelated data volumes;

refreshing the second data volume to the data contents of the first data volume that existed at time T, wherein refreshing the second data volume further comprises overwriting data of the second data volume with data of the first data volume that existed at time T,

generating first and second maps in memory, wherein

each of the first and second maps comprises

a plurality of entries, wherein

 

each entry of the first map corresponds to a respective memory block that stores data of the first data volume, and

 

each entry of the second map corresponds to a respective memory block that stores data of the second data volume,

setting a first bit in each entry of the first map, wherein

each first bit of the first map is set to indicate its respective memory block stores valid data, and

clearing a first bit in each entry of the second map, wherein

each first bit of the second map is set to indicate its respective memory block stores invalid data;

modifying data of the first data volume while the second data volume is being refreshed to the data contents of the first data volume that existed at time T;

modifying data of the second data volume while the second data volume is being refreshed to the data contents of the first data volume that existed at time T; and

modifying data of the first data volume after the second data volume has been refreshed.

2. The method of claim 1 further comprising creating one or more PIT copies of the first data volume prior to refreshing the second data volume to the data contents of the first data volume.

3. The method of claim 2 wherein one of the PIT copies of the first data volume is in a virtual state when the second data volume is refreshed to the data contents of the first data volume.

4. The method of claim 1 further comprising an act of preserving the second data volume, wherein said preserving comprises creating one or more PIT copies of the second data volume prior to refreshing the second data volume to the data contents of the first data volume.

5. The method of claim 4 wherein one of the PIT copies of the second data volume is in the virtual state when the second data volume is refreshed to the data contents of the first data volume.

6. The method of claim 1 wherein the first data volume is a real or virtual PIT copy of another data volume when the second data volume is refreshed to the data contents of the first data volume.

7. The method of claim 1 wherein the second data volume is a real or virtual PIT copy of another data volume when the second data volume is refreshed to the data contents of the first data volume.

8. The method of claim 1 further comprising:

setting or clearing a second bit in each entry of the second map to indicate that its respective memory block stores data needed for a PIT copy of the second data volume.

9. The method of claim 1 further comprising an act of preserving the second data volume, wherein said preserving comprises creating a PIT copy of the second data volume before or while refreshing the second data volume to the data contents of the first data volume.

10. A computer readable medium storing instructions executable by a computer system, wherein the computer system implements a method in response to executing the instructions, the method comprising:

writing data to a first and a second data volume, wherein

the first data volume is a first primary volume,

the second data volume is a second primary volume,

the first and second data volumes are unrelated data volumes;

refreshing the second data volume to the data contents of the first data volume that existed at time T, wherein refreshing the second data volume further comprises overwriting data of the second data volume with data of the first data volume that existed at time T,

generating first and second maps in memory, wherein

each of the first and second maps comprises

a plurality of entries, wherein

 

each entry of the first map corresponds to a respective memory block that stores data of the first data volume, and

 

each entry of the second map corresponds to a respective memory block that stores data of the second data volume,

setting a first bit in each entry of the first map, wherein

each first bit of the first map is set to indicate its respective memory block stores valid data, and

clearing a first bit in each entry of the second maps wherein

each first bit of the second map is set to indicate its respective memory block stores invalid data;

modifying data of the first data volume while the second data volume is being refreshed to the data contents of the first data volume that existed at time T;

modifying data of the second data volume while the second data volume is being refreshed to the data contents of the first data volume that existed at time T; and

modifying data of the first data volume after the second data volume has been refreshed.

11. The computer readable medium of claim 10 wherein the method further comprises creating one or more PIT copies of the first data volume prior to refreshing the second data volume to the data contents of the first data volume.

12. The computer readable medium of claim 11 wherein one of the PIT copies of the first data volume is in the virtual state when the second data volume is refreshed to the data contents of the first data volume.

13. The computer readable medium of claim 10 further comprising an act of preserving the second data volume, wherein said preserving further comprises creating one or more PIT copies of the second data volume prior to refreshing the second data volume to the data of the first data volume.

14. The computer readable medium of claim 13 wherein one of the PIT copies of the second data volume is in the virtual state when the second data volume is refreshed to the data contents of the first data volume.

15. The computer readable medium of claim 10 wherein the first data volume is a real or virtual PIT copy of another data volume when the second data volume is refreshed to the data contents of the first data volume.

16. The computer readable medium of claim 10 wherein the second data volume is a real or virtual PIT copy of another data volume when the second data volume is refreshed to the data contents of the first data volume.

17. The computer readable medium of claim 10 further comprising an act of preserving the second data volume, wherein said preserving further comprises creating a PIT copy of the second data volume before or while refreshing the second data volume to the data of the first data volume.