Multiple hierarchies of snapshots

Patent metadata

Field	Value
Publication number	US-10007448-B2
Application number	US-201514838629-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Aug 28, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A method for restoring a data volume using incremental snapshots of the data volume includes creating a first series of incremental snapshots according to a first predefined interval. The method further includes creating a second series of incremental snapshots according to a second predefined interval that is an integer multiple of the first predefined interval. The method also includes receiving a request to restore the data volume to a point-in-time. The method further includes restoring the data volume to the point-in-time using none or some of the snapshots in the first series that were created at or prior to the point-in-time, and all of the snapshots in the second series that were created at or prior to the point-in-time.

First claim

We claim:

1. A non-transitory computer readable medium comprising instructions that are executed in a computer system to carry out a method of restoring a data volume using incremental snapshots of the data volume, said method comprising:
creating a first series of incremental snapshots according to a first predefined interval;
creating a second series of incremental snapshots according to a second predefined interval, wherein the second predefined interval is different from the first predefined interval, and wherein the second predefined interval that is an integer multiple of the first predefined interval;
receiving a request to restore the data volume to a point-in-time; and
restoring the data volume to the point-in-time using none or some of the snapshots in the first series that were created at or prior to the point-in-time, and all of the snapshots in the second series that were created at or prior to the point-in-time.

2. The non-transitory computer-readable medium of claim 1 , wherein the method further comprises creating a snapshot of a base image of the data volume, and the base image is also used to restore the data volume to the point-in-time.

3. The non-transitory computer-readable medium of claim 2 , wherein a first of the snapshots in the first series was created after the first predefined interval after the snapshot of the base image of the data volume was created and a first of the snapshots in the second series was created after the second predefined interval after the snapshot of the base image of the data volume was created.

4. The non-transitory computer-readable medium of claim 3 , wherein if the point-in-time is aligned with a time when one of the snapshots in the second series was created, restoring the data volume to the point-in-time using none of the snapshots in the first series.

5. The non-transitory computer-readable medium of claim 3 , wherein if the point-in-time is aligned with a time when one of the snapshots in the first series was created but not with a time when one of the snapshots in the second series was created, restoring the data volume to the point-in-time using the snapshots in the first series that were created at or prior to the point-in-time and after the time of creating the most recent one of the snapshots in the second series that were created at or prior to the point-in-time.

6. The non-transitory computer-readable medium of claim 5 , wherein restoring the data volume to the point-in-time comprises:
creating a redo log for accepting write operations;
copying contents of the snapshots in the first series that were created at or prior to the point-in-time and after the time of creating the most recent one of the snapshots in the second series that were created at or prior to the point-in-time; and
directing read operations first to the redo log and then in time order, from most recent to least recent, to each of the snapshots in the second series that were created at or prior to the point-in-time, and then to the base image of the data volume.

7. The non-transitory computer-readable medium of claim 5 , wherein restoring the data volume to the point-in-time comprises:
creating a redo log for accepting write operations; and
directing read operations first to the redo log and then in time order, from most recent to least recent, to each of the snapshots in the first series that were created at or prior to the point-in-time and after the time of creating the most recent one of the snapshots in the second series that were created at or prior to the point-in-time, and then to the snapshots in the second series that were created at or prior to the point-in-time, and then to the base image of the data volume.

8. The non-transitory computer-readable medium of claim 1 , further comprising pruning one or more snapshots in the first series of snapshots, and merging one or more changes associated with the pruned one or more snapshots into another snapshot in either the first or second series of snapshots.

9. The non-transitory computer-readable medium of claim 8 , further comprising pruning a snapshot in the second series of snapshots because it no longer has any corresponding snapshots in the first series of snapshots.

10. The non-transitory computer-readable medium of claim 1 , further comprising:
creating a third series of incremental snapshots according to a third predefined interval that is an integer multiple or an integer divisor of the first predefined interval; and
restoring the data volume to the point-in-time using none or some of the snapshots in the third series that were created at or prior to the point-in-time.

11. A method for restoring a data volume using incremental snapshots of the data volume, said method comprising:
creating a first series of incremental snapshots according to a first predefined interval;
creating a second series of incremental snapshots according to a second predefined interval, wherein the second predefined interval is different from the first predefined interval, and wherein the second predefined interval is an integer multiple of the first predefined interval;
receiving a request to restore the data volume to a point-in-time; and
restoring the data volume to the point-in-time using none or some of the snapshots in the first series that were created at or prior to the point-in-time, and all of the snapshots in the second series that were created at or prior to the point-in-time.

12. The method of claim 11 , further comprising:
creating a snapshot of a base image of the data volume, wherein the base image is also used to restore the data volume to the point-in-time.

13. The method of claim 11 , wherein a first of the snapshots in the first series was created after the first predefined interval after the snapshot of the base image of the data volume was created and a first of the snapshots in the second series was created after the second predefined interval after the snapshot of the base image of the data volume was created.

14. The method of claim 13 , wherein if the point-in-time is aligned with a time when one of the snapshots in the first series was created but not with a point-in-time when one of the snapshots in the second series was created, restoring the data volume to the point-in-time using the snapshots in the first series that were created at or prior to the point-in-time and after the time of creating the most recent one of the snapshots in the second series that were created at or prior to the point-in-time.

15. The method of claim 14 , wherein restoring the data volume to the point-in-time comprises:
creating a redo log for accepting write operations;
copying contents of the snapshots in the first series that were created at or prior to the point-in-time and after the time of creating the most recent one of the snapshots in the second series that were created at or prior to the point-in-time; and
directing read operations first to the redo log and then in time order, from most recent to least recent, to each of the snapshots in the second series that were created at or prior to the point-in-time, and then to the base image of the data volume.

16. An apparatus, comprising:
a processing unit; and
a memory coupled to the processing unit, the memory storing instructions which, when executed by the processing unit, cause the processing unit to:
create a first series of incremental snapshots of a data volume according to a first predefined interval;
create a second series of incremental snapshots of the data volume according to a second predefined interval, wherein the second predefined interva

Assignees

• Vmware Inc

Inventors

• Zucca Michael
• Farkas Keith
• Ren Joanne
• Rawat Mayank
• Karamanolis Christos

Classifications

• G06F11/1448 Primary

  Management of the data involved in backup or backup restore · CPC title

• G06F3/0673

  Single storage device · CPC title

• G06F3/0619 Primary

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

• G06F3/0647

  Migration mechanisms · CPC title

• G06F11/1456

  Hardware arrangements for backup · CPC title