METHODS AND SYSTEMS FOR OPTIMAL SNAPSHOT DISTRIBUTION WITHIN A PROTECTION SCHEDULE

• US 20160139823A1
• Filed: 04/06/2015
• Published: 05/19/2016
• Est. Priority Date: 11/13/2014
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Nimble Storage (Hewlett-Packard Enterprise Company)
• Inventors: Costea, George, Forgette, Eric
• Granted Patent: US 9,727,252 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Storage administrators would like to create snapshots of a storage array as frequently as possible, but too many concurrent snapshots can place an unnecessary load on the storage array. Described herein are techniques for scheduling snapshots on the storage array with the objective of minimizing the maximum number of simultaneous snapshots and/or temporally spacing apart snapshots from each other.

Claims

1. A method, comprising:

for each of a plurality of candidate snapshot schedules, determining, by a snapshot scheduler of a storage array and based on one or more pre-existing snapshot schedules, the maximum number of snapshots that are simultaneously scheduled during a plurality of time instances within the candidate snapshot schedule;

selecting by the snapshot scheduler ones of the candidate snapshot schedules that are associated with the lowest maximum number of simultaneous snapshots; and

from the selected candidate snapshot schedules, selecting by the snapshot scheduler a subject one of the candidate snapshot schedules based on respective start times of the selected candidate snapshot schedules.

2. The method of claim 1, further comprising:

performing, by a snapshot manager of the storage array, snapshots of the storage array in accordance with the subject candidate snapshot schedule.

3. The method of claim 1, wherein the selection of the subject one of the candidate snapshot schedules comprises:

determining the longest sequence of consecutive start times of the selected candidate snapshot schedules;

determining a time at a midpoint of the longest sequence of consecutive start times; and

selecting the candidate snapshot schedule with a starting time at the midpoint time as the subject candidate snapshot schedule.

4. The method of claim 1, wherein each of the candidate snapshot schedules is defined by a start time, an end time, a period of time which separates temporally adjacent snapshots scheduled between the start time and end time, and days of the week during which snapshots are to be performed.

6. The method of claim 1, further comprising receiving by the snapshot scheduler a request to schedule snapshots.

7. The method of claim 6, wherein the request includes a protection schedule that specifies a start hour, an end hour and a snapshot interval at which snapshots are to be taken.

5. The method of claim 5, wherein the start time of each of the candidate snapshot schedules falls within a user-specified period of time.

8. A storage array, comprising:

a plurality of storage elements;

a main memory;

a processor communicatively coupled to the storage elements and the main memory; and

software instructions on the main memory that, when executed by the processor, cause the processor to;

for each of a plurality of candidate snapshot schedules, determine, based on one or more pre-existing snapshot schedules, the maximum number of snapshots that are simultaneously scheduled during a plurality of time instances within the candidate snapshot schedule;

select ones of the candidate snapshot schedules that are associated with the lowest maximum number of simultaneous snapshots; and

from the selected candidate snapshot schedules, select a subject one of the candidate snapshot schedules based on respective start times of the selected candidate snapshot schedules.

9. The storage array of claim 8, further comprising software instructions on the main memory that, when executed by the processor, cause the processor to perform snapshots of the storage array in accordance with the subject candidate snapshot schedule.

10. The storage array of claim 8, wherein the selection of the subject one of the candidate snapshot schedules comprises:

determining the longest sequence of consecutive start times of the selected candidate snapshot schedules;

determining a time at a midpoint of the longest sequence of consecutive start times; and

selecting the candidate snapshot schedule with a starting time at the midpoint time as the subject candidate snapshot schedule.

11. The storage array of claim 8, wherein each of the candidate snapshot schedules is defined by a start time, an end time, a period of time which separates temporally adjacent snapshots scheduled between the start time and end time, and days of the week during which snapshots are to be performed.

12. The storage array of claim 11, wherein the start time of each of the candidate snapshot schedules falls within a user-specified period of time.

13. The storage array of claim 8, further comprising software instructions on the main memory that, when executed by the processor, cause the processor to receive a request to schedule snapshots.

14. The storage array of claim 13, wherein the request includes a protection schedule that specifies a start hour, an end hour and a snapshot interval at which snapshots are to be taken.

15. A non-transitory machine-readable storage medium for a storage array having (i) a plurality of storage elements, (ii) a main memory, and (iii) a processor communicatively coupled to the storage elements and the main memory, the non-transitory machine-readable storage medium comprising software instructions that, when executed by the processor, cause the processor to:

for each of a plurality of candidate snapshot schedules, determine, based on one or more pre-existing snapshot schedules, the maximum number of snapshots that are simultaneously scheduled during a plurality of time instances within the candidate snapshot schedule;

select ones of the candidate snapshot schedules that are associated with the lowest maximum number of simultaneous snapshots; and

from the selected candidate snapshot schedules, select a subject one of the candidate snapshot schedules based on respective start times of the selected candidate snapshot schedules.

16. The non-transitory machine-readable storage medium of claim 15, further comprising software instructions that, when executed by the processor, cause the processor to perform snapshots of the storage array in accordance with the subject candidate snapshot schedule.

17. The non-transitory machine-readable storage medium of claim 15, wherein the selection of the subject one of the candidate snapshot schedules comprises:

determining the longest sequence of consecutive start times of the selected candidate snapshot schedules;

determining a time at a midpoint of the longest sequence of consecutive start times; and

selecting the candidate snapshot schedule with a starting time at the midpoint time as the subject candidate snapshot schedule.

18. The non-transitory machine-readable storage medium of claim 15, wherein each of the candidate snapshot schedules is defined by a start time, an end time, a period of time which separates temporally adjacent snapshots scheduled between the start time and end time, and days of the week during which snapshots are to be performed.

19. The non-transitory machine-readable storage medium of claim 18, wherein the start time of each of the candidate snapshot schedules falls within a user-specified period of time.

20. The non-transitory machine-readable storage medium of claim 15, further comprising software instructions that, when executed by the processor, cause the processor to receive a request to schedule snapshots, wherein the request includes a protection schedule that specifies a start hour, an end hour and a snapshot interval at which snapshots are to be taken.