Read Ahead Tiered Local and Cloud Storage System and Method Thereof

• US 20140244937A1
• Filed: 02/22/2013
• Published: 08/28/2014
• Est. Priority Date: 02/22/2013
• Status: Active Grant

• Current Assignee: Hitachi Vantara, LLC (Hitachi, Ltd.)
• Original Assignee: Bluearc UK Ltd. (Hitachi, Ltd.)
• Inventors: Bloomstein, Jason R., Meadows, Joseph, Bort-Shatsky, Inna
• Granted Patent: US 9,319,265 B2
• Time in Patent Office: Days
• US Class Current: 711/136
• 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 16/182 Distributed file systems
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

A high tier storage area stores a stub file and a lower tier cloud storage area stores the file corresponding to the stub file. When a client apparatus requests segments of the file from the high tier storage area, reference is made to the stub file to determine a predicted non-sequential pattern of requests to the segments by the client apparatus. The high tier storage area follows the predicted non-sequential pattern of requests to retrieve the segments of the file from the cloud prior to the client apparatus actually requesting the segments. As such, the file may be efficiently provided to the client apparatus while also efficiently storing the file on the lower tier cloud storage area.

Claims

1. A computer system connected over a network to a cloud service, the computer system comprising:

a storage area having a file system which includes a stub file representing a file stored with the cloud service; and

a cache and a processor connected to the primary storage system,

wherein an initial request for a first data segment of the file to the storage area causes the processor to refer to the stub file, issue a first request to the cloud service for the first data segment of the file stored with the cloud service, and store the first data segment of the file in the cache,

wherein, based on the initial request to the file, the processor issues a second request to the cloud service for a last data segment of the file stored with the cloud service, and stores the last data segment of the file in the cache, and,

wherein, after the second request for the last data segment, the processor issues one or more additional requests to the cloud service, based on the initial request to the file, for non-sequential intermediate data segments of the file stored with the cloud service, and stores the non-sequential intermediate data segments in the cache.

2. The computer system of claim 1, wherein requests, after the initial request, for non-sequential data segments of the file to the storage area, causes the processor to refer to the cache, and read the non-sequential data segments corresponding to the requests from the cache.

3. The computer system of claim 1, wherein the one or more additional requests are issued after the last data segment of the file is stored in the cache.

4. The computer system of claim 1, wherein the non-sequential intermediate data segments are interleaved data segments.

5. The computer system of claim 1, wherein the non-sequential intermediate data segments are 64k segments.

6. The computer system of claim 1, wherein the stub file includes metadata indicating a type of the file stored with the cloud service.

7. The computer system of claim 1, wherein the file system is CIFS.

8. The computer system of claim 1, wherein the first, second and additional requests to the cloud service are HTTPS requests.

9. The computer system of claim 1, further comprising a client computer which issues the initial request for the file, and reads the first, last and non-sequential intermediate data segments from the cache.

10. The computer system of claim 1, wherein the non-sequential intermediate data segments are removed on a FIFO basis.

11. The computer system of claim 1, wherein the non-sequential intermediate data segments are removed on a least recently accessed basis.

12. A method of retrieving a file, the method comprising:

storing a file with a cloud service and maintaining a stub file representing the file on a file system of a storage area connected over a network with the cloud service;

receiving at the storage area an initial request for a first data segment of the file;

referring to the stub file;

issuing a first request to the cloud service for the first data segment of the file stored with the cloud service;

storing the first data segment of the file in a cache accessible to the storage area;

issuing, based on the initial request, a second request to the cloud service for a last data segment of the file stored with the cloud service;

storing the last data segment of the file in the cache;

issuing, based on the initial request, one or more additional requests to the cloud service for non-sequential intermediate data segments of the file stored with the cloud service; and

storing the non-sequential intermediate data segments in the cache.

13. The method of claim 12, further comprising:

receiving, at the storage area and after the initial request, requests for the non-sequential data segments of the file; and

reading the non-sequential data segments corresponding to the requests from the cache.

14. The method of claim 12, wherein the one or more additional requests are issued after the last data segment of the file is stored in the cache.

15. The method of claim 12, wherein the non-sequential intermediate data segments are interleaved data segments.

16. The method of claim 12, wherein the non-sequential intermediate data segments are 64k segments.

17. The method of claim 12, wherein the stub file includes metadata indicating a type of the file stored with the cloud service.

18. The method of claim 12, wherein the file system is CIFS.

19. The method of claim 12, wherein the first, second and additional requests to the cloud service are HTTPS requests.

20. The method of claim 12, wherein a client computer issues the initial request for the file, and reads the first, last and non-sequential intermediate data segments from the cache.

21. The method of claim 12, further comprising:

removing the non-sequential intermediate data segments on a FIFO basis.

22. The method of claim 12, further comprising:

removing the non-sequential intermediate data segments on a least recently accessed basis.