Systems and methods for taking snapshots in a deduplicated virtual file system

• US 9,946,605 B2
• Filed: 11/25/2015
• Issued: 04/17/2018
• Est. Priority Date: 11/25/2015
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Inventors: Zhang, Xianbo, Wang, Haigang, Zhang, Shuangmin, Van Voorst, Jeffrey, Wu, Weibao, Kulkarni, Sameer, Joshi, Nilesh, Li, Kai, Yang, Yun, Brons, Scott
• Primary Examiner(s): Jacob, Ajith
• Application Number:
  US14/952,831
• Publication Number:
  US 20170147446A1
• Time in Patent Office: 874 Days
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/188 Virtual file systems
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0646 Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A computer-implemented method for taking snapshots in a deduplicated virtual file system may include (1) maintaining a deduplicated virtual file system that stores, at an original location within a non-virtual file system, at least one configuration file storing metadata for a target file and an extent map for the target file, the extent map defining how to construct the target file from deduplicated data segments in a deduplicated storage system, (2) receiving a request to take a snapshot of the target file corresponding to the configuration file, (3) copying the configuration file storing metadata for the target file and the extent map for the target file into a snapshot location within the non-virtual file system, and (4) transmitting a file reference request to the deduplicated storage system to add a file reference within the deduplicated storage system. Various other methods, systems, and computer-readable media are also disclosed.

Claims

1. A computer-implemented method for taking snapshots in a deduplicated virtual file system, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising:

maintaining a deduplicated virtual file system that stores, at an original location within a non-virtual file system, at least one configuration file storing metadata for a target file and an extent map for the target file, the extent map defining how to construct the target file from deduplicated data segments in a deduplicated storage system;

receiving a request to take a snapshot of the target file corresponding to the configuration file;

copying, in response to receiving the request to take the snapshot of the target file, the configuration file storing metadata for the target file and the extent map for the target file into a snapshot location within the non-virtual file system that is different than the original location;

transmitting, in response to receiving the request to take the snapshot of the target file, a file reference request to the deduplicated storage system to add a file reference within the deduplicated storage system, the file reference indicating that the snapshot of the target file references at least one deduplicated data segment within the deduplicated storage system.

2. The method of claim 1, wherein:

the configuration file stores at least the metadata for the target file;

the original location of the configuration file comprises a metadata directory.

3. The method of claim 1, wherein:

the configuration file stores at least the extent map for the target file;

the original location of the configuration file comprises a map directory.

4. The method of claim 1, wherein:

the original location of the configuration file comprises a directory;

the snapshot location of the configuration file comprises a subdirectory of the directory.

5. The method of claim 4, wherein the subdirectory of the directory is created in response to receiving the request to take the snapshot.

6. The method of claim 4, wherein creating the subdirectory of the directory comprises assigning the subdirectory a name of the snapshot that was assigned to the snapshot prior to creating the subdirectory.

7. The method of claim 1, wherein the at least one configuration file comprises:

a file storing the metadata for the target file;

a separate file storing the extent map for the target file.

8. The method of claim 1, further comprising:

identifying, by the deduplicated storage system, the deduplicated data segment referenced by the snapshot of the target file;

marking, by the deduplicated storage system, the deduplicated data segment as referenced by the snapshot of the target file to prevent removal of the deduplicated data segment.

9. The method of claim 8, further comprising marking, by the deduplicated storage system, each deduplicated data segment referenced by the snapshot of the target file as referenced by the snapshot of the target file to prevent removal of the respective deduplicated data segment.

10. The method of claim 1, further comprising:

modifying content of the snapshot;

modifying the extent map stored at the snapshot location to reference both;

an additional deduplicated data segment that the snapshot newly references due to the modifying;

an additional deduplication container storing the additional deduplicated data segment separate from an original deduplication container storing the deduplicated data segment of the snapshot prior to the modifying.

11. A system comprising:

a maintenance module, stored in memory, that maintains a deduplicated virtual file system that stores, at an original location within a non-virtual file system, at least one configuration file storing metadata for a target file and an extent map for the target file, the extent map defining how to construct the target file from deduplicated data segments in a deduplicated storage system;

a reception module, stored in memory, that receives a request to take a snapshot of the target file corresponding to the configuration file;

a copying module, stored in memory, that copies, in response to receiving the request to take the snapshot of the target file, the configuration file storing metadata for the target file and the extent map for the target file into a snapshot location within the non-virtual file system that is different than the original location;

a transmission module, stored in memory, that transmits, in response to receiving the request to take the snapshot of the target file, a file reference request to the deduplicated storage system to add a file reference within the deduplicated storage system, the file reference indicating that the snapshot of the target file references at least one deduplicated data segment within the deduplicated storage system;

at least one physical processor configured to execute the maintenance module, the reception module, the copying module, and the transmission module.

12. The system of claim 11, wherein:

the configuration file stores at least the metadata for the target file;

the original location of the configuration file comprises a metadata directory.

13. The system of claim 11, wherein:

the configuration file stores at least the extent map for the target file;

the original location of the configuration file comprises a map directory.

14. The system of claim 11, wherein:

the original location of the configuration file comprises a directory;

the snapshot location of the configuration file comprises a subdirectory of the directory.

15. The system of claim 14, wherein the subdirectory of the directory is created in response to receiving the request to take the snapshot.

16. The system of claim 14, wherein the copying module creates the subdirectory of the directory by assigning the subdirectory a name of the snapshot that was assigned to the snapshot prior to creating the subdirectory.

17. The system of claim 11, wherein the at least one configuration file comprises:

a file storing the metadata for the target file;

a separate file storing the extent map for the target file.

18. The system of claim 11, wherein the deduplicated storage system is programmed to:

identify the deduplicated data segment referenced by the snapshot of the target file;

mark the deduplicated data segment as referenced by the snapshot of the target file to prevent removal of the deduplicated data segment.

19. The system of claim 18, wherein the deduplicated storage system is programmed to mark each deduplicated data segment referenced by the snapshot of the target file as referenced by the snapshot of the target file to prevent removal of the respective deduplicated data segment.

20. A non-transitory computer-readable medium comprising one or more computer-readable instructions that, when executed by at least one processor of a computing device, cause the computing device to:

maintain a deduplicated virtual file system that stores, at an original location within a non-virtual file system, at least one configuration file storing metadata for a target file and an extent map for the target file, the extent map defining how to construct the target file from deduplicated data segments in a deduplicated storage system;

receive a request to take a snapshot of the target file corresponding to the configuration file;

copy, in response to receiving the request to take the snapshot of the target file, the configuration file storing metadata for the target file and the extent map for the target file into a snapshot location within the non-virtual file system that is different than the original location;

transmit, in response to receiving the request to take the snapshot of the target file, a file reference request to the deduplicated storage system to add a file reference within the deduplicated storage system, the file reference indicating that the snapshot of the target file references at least one deduplicated data segment within the deduplicated storage system.