Methods for replicating data and enabling instantaneous access to data and devices thereof

Patent metadata

Field	Value
Publication number	US-9773004-B2
Application number	US-201414522820-A
Country	US
Kind code	B2
Filing date	Oct 24, 2014
Priority date	Oct 24, 2014
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A method, non-transitory computer readable medium, and device that replicates data and provides instantaneous access to data includes receiving in a destination volume one or more named data extents and one or more references to the one or more named data extents associated with a file in parallel from a source volume. A determination is made to check whether the one or more references arrive before the one or more named data extents arrive. Each of the received one or more references which are determined to have arrived prior to the one or more data extents is allocated as absent by the storage management computing device. An instantaneous access to the file is provided during the allocation.

First claim

What is claimed is:

1. A method comprising:
facilitating replication of changed data from a first volume to a second volume;
receiving a data extent reference that references a data extent associated with a file of the changed data;
determining that the data extent reference is received before data extent content of the data extent;
performing an absent allocation for the data extent at the second volume based upon the data extent reference being received before the data extent content, wherein the absent allocation sets an absent allocated data block state for the data extent, the absent allocated data block state indicating that the data extent reference but not the data extent content is available at the second volume that is a destination for the replication; and
providing instantaneous access to the file during the absent allocation.

2. The method of claim 1 , comprising:
creating a data extent mapping between data extent references and data extent contents stored within the second volume.

3. The method of claim 2 , comprising:
resolving the data extent based on the data extent mapping.

4. The method of claim 3 , comprising:
adding the data extent at a referenced location, referenced by the data extent reference, within the file stored in the second volume.

5. The method of claim 1 , comprising:
adding the data extent content into the data extent of the file upon receipt of the data extent content after performance of the absent allocation.

6. The method of claim 5 , wherein the adding comprises:
adding the data extent to the file based on information from the first volume.

7. A non-transitory computer readable medium having stored thereon instructions, which when executed by a processor, causes the processor to:
facilitate replication of changed data from a first volume to a second volume;
receive a data extent reference that references a data extent associated with a file of the changed data;
determine that the data extent reference is received before data extent content of the data extent;
perform an absent allocation for the data extent at the second volume based upon the data extent reference being received before the data extent content, wherein the absent allocation sets an absent allocated data block state for the data extent, the absent allocated data block state indicating that the data extent reference but not the data extent content is available at the second volume that is a destination for the replication; and
provide instantaneous access to the file during the absent allocation.

8. The non-transitory computer readable medium of claim 7 , comprising:
creating a data extent mapping between data extent references and data extent contents stored within the second volume.

9. The non-transitory computer readable medium of claim 8 , comprising:
resolving the data extent based on the data extent mapping.

10. The non-transitory computer readable medium of claim 9 , comprising:
adding the data extent at a referenced location, referenced by the data extent reference, within the file stored in the second volume.

11. The non-transitory computer readable medium of claim 7 , comprising:
adding the data extent content into the data extent of the file upon receipt of the data extent content after performance of the absent allocation.

12. The non-transitory computer readable medium of claim 11 , wherein the adding comprises:
adding the data extent to the file based on information from the first volume.

13. A computing device comprising:
a memory containing computer-readable storage medium having stored thereon instructions for performing a method; and
a processor coupled with the memory, the processor configured to execute the instructions to cause the processor to:
facilitate replication of changed data from a first volume to a second volume;
receive a data extent reference that references a data extent associated with a file of the changed data;
determine that the data extent reference is received before data extent content of the data extent;
perform an absent allocation for the data extent at the second volume based upon the data extent reference being received before the data extent content, wherein the absent allocation sets an absent allocated data block state for the data extent, the absent allocated data block state indicating that the data extent reference but not the data extent content is available at the second volume that is a destination for the replication; and

provide instantaneous access to the file during the absent allocation.

14. The computing device of claim 13 , wherein the instructions cause the processor to:
create a data extent mapping between data extent references and data extent contents stored within the second volume.

15. The computing device of claim 14 , wherein the instructions cause the processor to:
resolve the data extent based on the data extent mapping.

16. The computing device of claim 15 , wherein the instructions cause the processor to:
add the data extent at a referenced location, referenced by the data extent reference, within the file stored in the second volume.

17. The computing device of claim 13 , wherein the instructions cause the processor to:
add the data extent content into the data extent of the file upon receipt of the data extent content after performance of the absent allocation.

18. The computing device of claim 17 , wherein the instructions cause the processor to:
adding the data extent to the file based on information from the first volume.

Assignees

• Netapp Inc

Inventors

• Curley Jonathan
• Simharajan Srishylam
• Shah Devang
• Jernigan Richard

Classifications

• G06F17/30082 Primary

  Physics · mapped topic

• G06F17/30215

  Physics · mapped topic

• G06F16/119

  Details of migration of file systems (migration mechanisms in storage systems G06F3/0647) · CPC title

• G06F3/0647

  Migration mechanisms · CPC title

• G06F16/1844

  Management specifically adapted to replicated file systems · CPC title