Methods for managing read access of objects in storage media and devices thereof

Patent metadata

Field	Value
Publication number	US-9851908-B2
Application number	US-201414164028-A
Country	US
Kind code	B2
Filing date	Jan 24, 2014
Priority date	Jan 24, 2014
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A method, device and non-transitory computer readable medium that manages read access includes organizing a plurality of requests for objects on one or more storage media, such as tapes or spin-down disks, based on at least a deadline for each of the plurality of requests. One of one or more replicas for each of the objects on the one or more storage media is selected based on one or more factors. An initial schedule for read access is generated based at least on the deadline for each of the plurality of requests, the selected one of the replicas for each of the objects, and availability of one or more drives. The initial schedule for read access on the one or more of the drives for each of the plurality of requests for the objects is provided.

First claim

What is claimed is:

1. A method comprising:
organizing, with a computing device, a plurality of requests for objects located on one or more storage media based on at least a deadline for each of the plurality of requests;
selecting, with the computing device, one of one or more replicas for each of the requested objects located on the one or more storage media based on a minimum number of violations of deadlines for the plurality of requests;
generating, with the computing device, an initial schedule for read access based at least on the selected replicas for each of the requested objects, and availability of at least one of the one or more storage media; and
providing, with the computing device, the initial schedule for read access on the at least one of the one or more storage media for each of the plurality of requests for the objects.

2. The method as set forth in claim 1 further comprising identifying, with the computing device, the one or more of the replicas for each of the objects on the one or more storage media.

3. The method as set forth in claim 1 further comprising selecting, with the computing device, one of one or more replicas for each of the objects on the one or more storage media based on a minimum load and unload time or a minimum read execution time.

4. The method as set forth in claim 1 further comprising:
determining, with the computing device, when two or more of the selected replicas in the initial schedule are selected on different ones of the storage media and have corresponding replicas available on the same one of the storage media; and
modifying, with the computing device, the initial schedule so the selection of the determined two or more replicas are changed to the corresponding replicas available on the same one of the storage media.

5. The method as set forth in claim 4 further comprising:
determining, with the computing device, when the modified schedule would violate the deadline for any request in the plurality of requests;
wherein if the modified schedule violate the deadline for any request in the plurality of requests, providing the initial schedule for read access; and
wherein if the modified schedule does not violate the deadline for any request in the plurality of requests, providing the modified schedule.

6. The method as set forth in claim 5 , further comprising:
determining, with the computing device, when two or more of the selected replicas on the same one of the storage media are on either the initial schedule or the modified schedule is in an access order which is not sequential; and
reordering, with the computing device, either the initial schedule or the modified schedule so the two or more of the selected replicas on the same one of the storage media are in an access order which is sequential.

7. The method as set forth in claim 6 further comprising:
determining, with the computing device, when the reordered schedule would violate the deadline for any request in the plurality of requests;
wherein if the reordered schedule violate the deadline for any request in the plurality of requests, providing either the initial schedule or the modified schedule for read access; and
wherein if the reordered schedule does not violate the deadline for any request in the plurality of requests, providing the reordered schedule.

8. The method as set forth in claim 1 wherein generating the initial schedule further comprises generating, with the computing device, the initial schedule for read access of the plurality of requests on the at least one of the storage media based on a single load of each of the one or more storage media needed for the plurality of requests.

9. The method as set forth in claim 1 , wherein generating the initial schedule further comprises generating, with the computing device, the initial schedule for read access of the plurality of requests on the at least one storage media based on use of deduplication window.

10. A computing device, comprising:
at least one processor;
at least one memory coupled to the processor configured to execute programmed instructions stored in the memory, comprising:
organizing a plurality of requests for objects located on one or more storage media based on at least a deadline for each of the plurality of requests;
selecting one of one or more replicas for each of the requested objects located on the one or more storage media based on a minimum number of violations of deadlines for the plurality of requests;
generating an initial schedule for read access based at least on the selected replicas for each of the requested objects, and availability of at least one of the one or more storage media; and
providing the initial schedule for read access on the at least one of the one or more storage media for each of the plurality of requests for the objects.

11. The device as set forth in claim 10 wherein the processor is further configured to execute programmed instructions stored in the memory further comprising identifying the one or more of the replicas for each of the objects on the one or more storage media.

12. The device as set forth in claim 10 further comprising selecting, with the computing device, one of one or more replicas for each of the objects on the one or more storage media based on a minimum load and unload time or a minimum read execution time.

13. The device as set forth in claim 10 wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:
determining when two or more of the selected replicas in the initial schedule are selected on different ones of the storage media and have corresponding replicas available on the same one of the storage media; and
modifying the initial schedule so the selection of the determined two or more replicas are changed to the corresponding replicas available on the same one of the storage media.

14. The device as set forth in claim 13 wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:
determining when the modified schedule would violate the deadline for any request in the plurality of requests;
wherein if the modified schedule violate the deadline for any request in the plurality of requests, providing the initial schedule for read access; and
wherein if the modified schedule does not violate the deadline for any request in the plurality of requests, providing the modified schedule.

15. The device as set forth in claim 14 wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:
determining when two or more of the selected replicas on the same one of the storage media are on either the initial schedule or the modified schedule is in an access order which is not sequential; and
reordering either the initial schedule or the modified schedule so the two or more of the selected replicas on the same one of the storage media are in an access order which is sequential.

16. The device as set forth in claim 15 wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:
determining when the reordered schedule would violate the deadline for any request in the plurality of requests;
wherein if the reordered schedule violate the deadline for any request in the plurality of requests, providing either the initial schedule or the modified schedule for read access; and
wherein if the reordered schedule does not violate the deadline for any request in the plurality of requests, providing the

Assignees

• Netapp Inc

Inventors

• Kathpal Atish
• Yasa Giridhar Appaji Nag

Classifications

• G06F2003/0698

  Physics · mapped topic

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F3/0619 Primary

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F3/065

  Replication mechanisms · CPC title

• G06F3/0686

  Libraries, e.g. tape libraries, jukebox · CPC title