Incremental access requests for portions of files from a cloud archival storage tier

1. A method, comprising:

receiving, at a storage system, a request to restore one or more files to a primary storage system;

determining that the one or more requested files have been archived at an archival storage tier of a cloud storage;

requesting, from a cloud storage provider, access to a first portion of the one or more requested files stored at the archival storage tier, wherein in response to the access request, the cloud storage provider changes a storage class associated with the first portion of the one or more requested files from the archival storage tier of the cloud storage to a different storage tier of the cloud storage that stores files accessed more than a threshold number of times within a threshold period;

providing, by the storage system, the access to the first portion in response to the request to restore the one or more files to the primary storage system in part by:

partially reconstructing, by the storage system, a tree data structure associated with one or more requested files, and

restoring, by the storage system, the first portion of the one or more requested files from the different storage tier of the cloud storage to the primary storage system via the storage system, wherein the storage system utilizes the partially reconstructed tree data structure associated with the one or more requested files to restore the first portion of the one or more requested files; and

based at least in part on a metric associated with a utilization of the first portion, determining when to request access to a second portion of the one or more requested files stored at the archival storage tier.

2. The method of claim 1 , wherein the one or more requested files are determined to have been archived at the archival storage tier based on an index stored at the storage system.

3. The method of claim 2 , wherein the index associates a file identifier associated with a file of the one or more requested files with a corresponding storage location.

4. The method of claim 1 , wherein requesting access to the first portion of the one or more requested files stored at the archival storage tier includes requesting a storage class for the first portion of the one or more requested files to be changed from the archival storage tier to the different storage tier of the cloud storage.

5. The method of claim 4 , wherein a size of the first portion of the one or more requested files corresponds to a storage threshold associated with the different storage tier.

6. The method of claim 1 , wherein providing the access to the first portion includes traversing and updating a partially restored tree data structure based on data associated with the first portion of the one or more requested files stored at the different storage tier of the cloud storage.

7. The method of claim 6 , wherein providing the access to the first portion further includes restoring the data associated with the first portion of the one or more requested files from the different storage tier of the cloud storage to the primary storage system.

8. The method of claim 1 , wherein providing the access to the first portion includes requesting the cloud storage provider to change a storage class for data associated with a file included in the first portion of the one or more requested files after the data associated with the file included in the first portion of the one or more requested files is restored from the different storage tier of the cloud storage to the primary storage system.

9. The method of claim 1 , further comprising:

monitoring a rate at which data associated with the first portion of the one or more requested files is being restored from the different storage tier of the cloud storage to the primary storage system; and

adjusting when to request the access to the second portion of the one or more requested files stored at the archival storage tier.

10. The method of claim 1 , wherein the metric associated with the utilization of the first portion is based in part on a rate at which the cloud storage provider is able to change a storage class for data associated with the first portion of the one or more requested files from the archival storage tier to the different storage tier of the cloud storage.

11. The method of claim 1 , wherein the metric associated with the utilization of the first portion is based in part on a rate at which the storage system is able to restore data associated with the first portion of the one or more requested files from the different storage tier of the cloud storage to the primary storage system.

12. The method of claim 1 , further comprising requesting the access to one or more additional portions of the one or more requested files stored at the archival storage tier.

13. The method of claim 12 , wherein requesting access to one or more additional portions of the one or more requested files is requested prior to a previous portion of one or more portions of the one or more requested files being completely restored to the primary storage system.

14. The method of claim 12 , further comprising providing the access to the one or more additional portions of the one or more requested files stored at the archival storage tier.

15. The method of claim 14 , wherein providing the access to the one or more additional portions of the one or more requested files stored at the archival storage tier includes requesting that one of the one or more additional portions of the one or more requested files stored at the different storage tier of the cloud storage be stored in the different storage tier of the cloud storage beyond a threshold period in the event a previous portion of the one or more requested files is unable to be restored to the primary storage system within a threshold amount of time.

16. The method of claim 12 , wherein requesting the access to the one or more additional portions of the one or more requested files is based at least in part on at least one of an amount of data that is to be included in an additional portion, a quality of service, a priority of request, and/or a time of a request.

17. A computer program product embodied in a non-transitory computer readable medium and comprising computer instructions for:

receiving, at a storage system, a request to restore one or more files to a primary storage system;

determining that the one or more requested files have been archived at an archival storage tier of a cloud storage;

requesting, from a cloud storage provider, access to a first portion of the one or more requested files stored at the archival storage tier, wherein in response to the access request, the cloud storage provider changes a storage class associated with the first portion of the one or more requested files from the archival storage tier of the cloud storage to a different storage tier of the cloud storage that stores files accessed more than a threshold number of times within a threshold period;

providing, by the storage system, the access to the first portion in response to the request to restore the one or more files to the primary storage system in part by:

partially reconstructing, by the storage system, a tree data structure associated with one or more requested files, and

restoring, by the storage system, the first portion of the one or more requested files from the different storage tier of the cloud storage to the primary storage system via the storage system, wherein the storage system utilizes the partially reconstructed tree data structure associated with the one or more requested files to restore the first portion of the one or more requested files; and

based at least in part on a metric associated with a utilization of the first portion, determining when to request access to a second portion of the one or more requested files stored at the archival storage tier.

18. The computer program product of claim 17 , further comprising computer instructions for requesting access to one or more additional portions of the one or more requested files stored at the archival storage tier.

19. The computer program product of claim 18 , wherein requesting access to one or more additional portions of the one or more requested files is requested prior to a previous portion of one or more portions of the one or more requested files being completely restored to the primary storage system.

20. A system, comprising:

a processor configured to:

receive, at a storage system, a request to restore one or more files to a primary storage system;

determine that the one or more requested files have been archived at an archival storage tier of a cloud storage;

request, from a cloud storage provider, access to a first portion of the one or more requested files stored at the archival storage tier, wherein in response to the access request, the cloud storage provider changes a storage class associated with the first portion of the one or more requested files from the archival storage tier of the cloud storage to a different storage tier of the cloud storage that stores files accessed more than a threshold number of times within a threshold period;

provide, by the storage system, the access to the first portion in response to the request to restore the one or more files to the primary storage system in part by:

partially reconstructing, by the storage system, a tree data structure associated with one or more requested files, and

restoring, by the storage system, the first portion of the one or more requested files from the different storage tier of the cloud storage to the primary storage system via the storage system, wherein the storage system utilizes the partially reconstructed tree data structure associated with the one or more requested files to restore the first portion of the one or more requested files; and

based at least in part on a metric associated with a utilization of the first portion, determine when to request access to a second portion of the one or more requested files stored at the archival storage tier; and

a memory coupled to the processor and configured to provide the processor with instructions.