Systems and methods for portals into snapshot data

• US 20090055604A1
• Filed: 08/21/2007
• Published: 02/26/2009
• Est. Priority Date: 08/21/2007
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Schack, Darren P., Lemar, Eric M., Fachan, Neal T.
• Granted Patent: US 7,949,692 B2
• Time in Patent Office: Days
• US Class Current: 711/161
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• 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 16/174 Redundancy elimination performed by the file system management of the data involved in backup or backup restore using de-duplication of the data G06F11/14
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

In one embodiment, a user or client device communicates with a distributed file system comprised of one or more physical nodes. The data on each of the physical nodes store metadata about files and directories within the file system. Some of the embodiments permit a user to take a snapshot of data stored on the file system. The snapshot may include a single file, a single directory, a plurality of files within a directory, a plurality of directories, a path on the file system that includes nested files and subdirectories, or more than one path on the file system that each includes nested files and directories. In some embodiments, systems and methods intelligently choose whether to use copy-on-write or point-in-time copy when saving data in a snapshot version of a file whose current version is being overwritten. In some embodiments, systems and methods allow snapshot users to return from a snapshot directory to the immediate parent directory from which the user entered into the snapshot.

Claims

1. A method of ascending a file system capable of distinguishing, based on relative depth, between multiple unique paths to the same directory, the method comprising:

receiving a request to ascend from a child directory to an expected parent directory, the expected parent directory being one of multiple possible parent directories;

determining the expected parent directory by evaluating, in part, a relative depth value of the child directory; and

ascending to the expected parent directory.

2. The method of claim 1, wherein the ascending to the expected parent directory is part of ascending the file system through a path that was taken when descending the file system.

3. The method of claim 1, wherein the file system is a distributed file system.

4. The method of claim 2, wherein the file system is a distributed file system.

5. The method of claim 1, wherein the file system is a multiple-version file system comprising current versions of data, snapshot versions of data, and portals to snapshots of data.

6. The method of claim 2, wherein the file system is a multiple-version File system comprising current versions of data, snapshot versions of data, and portals to snapshots of data.

7. The method of claim 5, wherein the snapshot versions of data are per-directory snapshots.

8. The method of claim 5, wherein the child directory is a snapshot version of data.

9. The method of claim 8, further comprising calculating the relative depth when descending into the child directory.

10. The method of claim 5, wherein the expected parent directory comprises one of the following:

a snapshot version of data, a portal to snapshot data, and a current version of data.

11. The method of claim 5, wherein the determining further comprises determining whether the child directory is one of the following:

a current version of data, a portal to snapshot data, and a snapshot version of data.

12. The method of claim 5, wherein the relative depth is relative to one of the following:

a snapshot version of data, a portal to snapshot data, and a current version of data.

13. A system capable of ascending a file system by distinguishing, based on relative depth, between multiple unique paths to the same directory, the system comprising:

a processor;

a memory system coupled to the processor, the memory system storing a file system; and

a navigation module comprising instructions executable by the processor to operate on the file system, the instructions comprising;

receiving a request to ascend from a child directory to an expected parent directory, the expected parent directory being one of multiple possible parent directories;

determining the expected parent directory by evaluating, in part, a relative depth value of the child directory; and

ascending to the expected parent directory.

14. The system of claim 13, wherein the ascending to the expected parent directory is part of ascending the file system through a path that was taken when descending the file system.

15. The system of claim 13, wherein the file system is a distributed file system.

16. The system of claim 14, wherein the file system is a distributed file system.

17. The system of claim 13, wherein the file system is a multiple-version file system comprising current versions of data, snapshot versions of data, and portals to snapshots of data.

18. The system of claim 14, wherein the file system is a multiple-version file system comprising current versions of data, snapshot versions of data, and portals to snapshots of data.

19. The system of claim 17, wherein the snapshot versions of data are per-directory snapshots.

20. The system of claim 17, wherein the child directory is a snapshot version of data.

21. The system of claim 20, wherein the instructions further comprise calculating the relative depth when descending into the child directory.

22. The system of claim 17, wherein the expected parent directory comprises one of the following:

a snapshot version of data, a portal to snapshot data, and a current version of data.

23. The system of claim 17, wherein the determining further comprises determining whether the child directory is one of the following:

a current version of data, a portal to snapshot data, and a snapshot version of data.

24. The system of claim 17, wherein the relative depth is relative to one of the following:

a snapshot version of data, a portal to snapshot data, and a current version of data.