PREDICTIVE POINT-IN-TIME COPY FOR STORAGE SYSTEMS

• US 20150309745A1
• Filed: 06/13/2013
• Published: 10/29/2015
• Est. Priority Date: 12/18/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wilkinson, John P.
• Granted Patent: US 9,857,996 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/2056 by mirroring
• CPC Class Codes: G06F 3/061 Improving I/O performance
• 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 3/067 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

Abstract

Method and system are provided for predictive point-in-time copy for storage systems. The method may include: recording a frequency of writes to an area of a storage volume; and prioritising areas for having point-in-time copies carried out based on the write frequency to an area, wherein areas in the storage volume having a high write frequency are prioritised before areas with a lower write frequency. An area may be of a coarser granularity than a region tracked for the point-in-time copy. The method may include: recording the frequency of writes to an area in a given period; and prioritising areas by their frequency of writes in the given period immediately prior to the point-in-time copy.

Claims

1. A method for predictive point-in-time copy for storage systems, comprising:

recording a frequency of writes to an area of a storage volume; and

prioritising areas for having point-in-time copies carried out based on the write frequency to an area, wherein areas in the storage volume having a high write frequency are prioritised before areas with a lower write frequency.

2. The method as recited in claim 1, wherein an area is the same or of a coarser granularity than a region tracked for the point-in-time copy.

3. The method as recited in claim 1, including:

recording the frequency of writes to an area in a given period; and

prioritising areas by their frequency of writes in the given period immediately prior to performing a point-in-time copy.

4. The method as recited in claim 1, including:

recording the frequency of writes to an area as a rolling count of writes; and

prioritising areas by a rolling ranking of writes at a given time of a point-in-time copy.

5. The method as recited in claim 1, including:

running a point-in-time copy when a write rate is below an average write rate.

6. The method as recited in claim 1, wherein prioritising areas includes:

determining a time of a previous point-in-time copy for the volume; and

weighting recordings of writes which occur nearest to the time of the previous point-in-time copy.

7. The method as recited in claim 6, including:

defining time segments from the time of the previous point-in-time copy and weighting writes according to the segment in which they take place.

8. The method as recited in claim 1, including:

initially synchronising a point-in-time copy for a volume and only copying newly-written regions of a volume in subsequent point-in-time copies; and

prioritising partial writes to an area.

9. The method as recited in claim 1, wherein recording a frequency of writes to an area of a storage volume includes:

intercepting input and outputs of a host server.

10. The method as recited in claim 1, including intelligently varying a background copy rate to increase the rate during periods of fewer writes.

11. A system for predictive point-in-time copy for storage systems, comprising:

an area use recorder for recording a frequency of writes to an area of a storage volume; and

an area ordering component for prioritising areas for having point-in-time copies carried out based on the write frequency to an area, wherein areas in the storage volume having a high write frequency are prioritised before areas with a lower write frequency.

12. The system as recited in claim 11, wherein an area is the same or of a coarser granularity than a region tracked for the point-in-time copy.

13. The system as recited in claim 11, wherein the area use recorder is configured to:

record the frequency of writes to an area in a given period; and

prioritise areas by their frequency of writes in the given period immediately prior to the point-in-time copy.

14. The system as recited in claim 11, wherein the area use recorder is configured to:

record the frequency of writes to an area as a rolling count of writes; and

prioritise areas by a rolling ranking of writes at a given time of a point-in-time copy.

15. The system as recited in claim 11, including:

a background copy control component for running a point-in-time copy when a write rate is below an average write rate.

16. The system as recited in claim 11, wherein the area ordering component is configured to:

determine a time of a previous point-in-time copy for the volume; and

provide a weighting for recordings of writes which occur nearest to the time of the previous point-in-time copy.

17. The system as recited in claim 16, wherein the area ordering component is configured to define time segments from the time of the previous point-in-time copy and to weight writes according to the segment in which they take place.

18. The system as recited in claim 11, wherein the area use recorder is configured to:

initially synchronise a point-in-time copy for a volume and only copy newly-written regions of a volume in subsequent point-in-time copies; and

prioritise partial writes to an area.

19. The system as recited in claim 11, including a background copy control component for intelligently varying a background copy rate to increase the rate during periods of fewer writes.

20. A computer program product for predictive point-in-time copy for storage systems, the computer program product comprising:

a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit to cause the processing circuit to perform a method comprising;

recording a frequency of writes to an area of a storage volume; and

prioritising areas for having point-in-time copies carried out based on the write frequency to an area, wherein areas in the storage volume having a high write frequency are prioritised before areas with a lower write frequency.

21. (canceled)

22. (canceled)

23. (canceled)