Instant refresh of a data volume copy

• US 20050169064A1
• Filed: 02/28/2005
• Published: 08/04/2005
• Est. Priority Date: 12/19/2002
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (NortonLifeLock Inc.)
• Inventors: Kiselev, Oleg, Colgrove, John A., Kekre, Anand A.
• Granted Patent: US 7,337,288 B2
• Time in Patent Office: Days
• US Class Current: 365/189.50
• 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: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

Disclosed is a method and apparatus for refreshing a copy of a data volume. In one embodiment of the method first and second data portions of a data volume are copied to first and second memory blocks, respectively, of a memory coupled to a computer system. First and second bits of a first map stored in memory are then set, wherein the first and second bits correspond to the first and second memory blocks, respectively. The first data portion of the data volume is modified after the first data portion is copied to the first memory block. A first bit in a second map stored in memory is set after data of the first data portion is modified. An instruction is generated to refresh the data contents of the first and second memory blocks. The first bit of the first map is cleared in response to generation of the refresh instruction.

Claims

1-20. -20. (canceled)

21. A method comprising:

creating a first virtual point-in-time (PIT) copy of a data volume;

modifying first data within the data volume after creation of the first PIT virtual copy;

refreshing the first PIT virtual copy to create a second PIT virtual copy of the data volume, wherein the first PIT virtual copy is refreshed after modification of the first data within the data volume.

22. The method of claim 21 further comprising:

generating a refresh instruction, wherein the first PIT virtual copy is refreshed in response to generation of the refresh instruction, wherein the refresh instruction is generated after modifying the first data;

in response to generation of the refresh instruction, copying the modified first data from a first memory to a second memory that stores data of the first virtual copy;

modifying second data of the data volume, wherein the second data is modified after generation of the refresh instruction, and wherein the second data is modified before the modified first data is copied to the second memory.

23. The method of claim 22 further comprising transforming the second PIT virtual copy into a real PIT copy, wherein the second data is modified before the second PIT virtual copy is transformed into the real PIT copy.

24. The method of claim 21 further comprising:

creating a PIT copy of the first PIT virtual copy;

generating a second refresh instruction;

refreshing the PIT copy to create a third virtual PIT copy of the data volume in response to generating the second refresh instruction.

25. The method of claim 21 further comprising:

creating a PIT copy of the first PIT virtual copy;

generating a second refresh instruction;

refreshing the PIT copy to create another PTI copy of the first PIT virtual copy in response to generating the second refresh instruction.

26. The method of claim 24 further comprising:

modifying third data of the data volume after creating the first PIT virtual copy, wherein the second refresh instruction is generated after modifying the third data;

in response to generation of the second refresh instruction, copying the modified third data to a third memory;

modifying fourth data of the data volume, wherein the fourth data is modified after generation of the second refresh instruction, and wherein the fourth data is modified before the modified third data is copied to the third memory.

27. A method comprising:

storing data in a plurality of first memory blocks;

copying data from several of the first memory blocks to several of a plurality of second memory blocks, respectively;

switching the state of several second bits in memory in response to copying data from the several first memory blocks to the several second memory blocks, respectively, wherein each of the second bits corresponds to a respective second memory block;

modifying data stored in one of the several first memory blocks after copying data from the several first memory blocks to the several second memory blocks, respectively;

switching the state of a first bit in memory in response to modifying data stored in the one of the several first memory blocks, wherein the first bit corresponds to the one of the several first memory blocks;

generating a refresh instruction, wherein the refresh instruction is generated after modifying data stored in the one of the several first memory blocks;

switching the state of the one of the several second bits in response to the generation of the refresh instruction.

28. The method of claim 27 further comprising switching the state of the one of the several first bits back to its original state in response to the generation of the instruction to refresh.

29. A computer readable medium comprising instructions executable by a computer system to implement a method, the method comprising:

copying first and second data portions of a data volume to first and second memory blocks, respectively, of a memory coupled to the computer system;

setting first and second bits stored of a first map in memory, wherein the first and second bits correspond to the first and second memory blocks, respectively;

modifying data of the first data portion of the data volume after the first data portion is copied to the first memory block;

setting a first bit in a second map stored in memory after data of the first data portion is modified;

generating an instruction to refresh;

clearing the first bit of the first map in response to generation of the refresh instruction.

30. The computer readable medium of claim 29 wherein the method further comprises:

overwriting the first data portion in the first memory block with the modified data;

modifying the second data portion of the data volume after the first data portion is copied to the first memory block, after generation of the refresh instruction, and before the first memory block is overwritten with the first modified data.

31. A computer readable medium comprising instructions executable by a computer system to implement a method, the method comprising:

creating a first virtual point-in-time (PIT) copy of a data volume;

refreshing the first PIT virtual copy to create a second PIT virtual copy of the data volume, wherein the first PIT virtual copy is refreshed after modification of first data within the data volume.

32. The computer readable medium of claim 31 wherein the method further comprises:

generating a refresh instruction, wherein the first PIT virtual copy is refreshed in response to generation of the refresh instruction, wherein the refresh instruction is generated after modifying the first data;

in response to generation of the refresh instruction, copying the modified first data from a first memory to a second memory that stores data of the first virtual copy;

modifying second data of the data volume, wherein the second data is modified after generation of the refresh instruction, and wherein the second data is modified before the modified first data is copied to the second memory.

33. The computer readable medium of claim 32 wherein the method further comprises transforming the second PIT virtual copy into a real PIT copy, wherein the second data is modified before the second PIT virtual copy is transformed into the real PIT copy.

34. The computer readable medium of claim 31 wherein the method further comprises:

creating a PIT copy of the first PIT virtual copy;

generating a second refresh instruction;

refreshing the PIT copy to create a third virtual PIT copy of the data volume in response to generating the second refresh instruction.

35. The computer readable medium of claim 31 wherein the method further comprises:

creating a PIT copy of the first PIT virtual copy;

generating a second refresh instruction;

refreshing the PIT copy to create another PTI copy of the first PIT virtual copy in response to generating the second refresh instruction.

36. The computer readable medium of claim 34 wherein the method further comprises:

modifying third data of the data volume after creating the first PIT virtual copy, wherein the second refresh instruction is generated after modifying the third data;

in response to generation of the second refresh instruction, copying the modified third data to a third memory;

modifying fourth data of the data volume, wherein the fourth data is modified after generation of the second refresh instruction, and wherein the fourth data is modified before the modified third data is copied to the third memory.