Asynchronous replication by tracking recovery point objective

• US 8,332,354 B1
• Filed: 12/15/2009
• Issued: 12/11/2012
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: AmZetta Technologies, LLC (American Megatrends International, LLC)
• Original Assignee: American Megatrends Incorporated
• Inventors: Chatterjee, Paresh, Jayaraman, Raja, Ranganathan, Loganathan, Maliakal, Jomy
• Primary Examiner(s): Ehichioya, Fred I
• Assistant Examiner(s): Fan, Shiow-Jy
• Application Number:
  US12/638,783
• Time in Patent Office: 1,092 Days
• Field of Search: 707/999.2, 707/610, 707/E17.007, 707/999.1, 707/624, 707/639
• US Class Current: 707/624
• CPC Class Codes: G06F 11/1461 Backup scheduling policy
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

Technologies are described herein for skipping snapshots during a snapshot replication process in order to maintain an established recovery point objective. A first snapshot is selected after a previously replicated snapshot. A creation time of the first snapshot is retrieved. A difference between a current time and the creation time of the first snapshot is computed. A determination is made as to whether the difference is less than a recovery point objective. If the difference is less than a recovery point objective, then the first snapshot is replicated in the snapshot replicated process. If the difference is not less than a recovery point objective, then the first snapshot is skipped through the snapshot replication process.

Claims

1. A computer-implemented method for skipping snapshots during a snapshot replication process, the computer-implemented method comprising computer-implemented operations for:

if a basis for skipping snapshots is time-related, skipping snapshots based on time-related parameters includes;

selecting a first snapshot created subsequently to a previously replicated snapshot, the previously replicated snapshot comprising at least a portion of a snapshot created prior to the first snapshot;

retrieving a creation time of the first snapshot;

computing a time difference between a current time and the creation time of the first snapshot;

determining whether the time difference between the current time and the creation time of the first snapshot is less than a recovery point objective;

in response to determining that the time difference between the current time and the creation time of the first snapshot is less than the recovery point objective, replicating the first snapshot in the snapshot replication process; and

in response to determining that the time difference between the current time and the creation time of the first snapshot is not less than the recovery point objective, skipping the first snapshot through the snapshot replication process;

if a basis for skipping snapshots is delta-data related, skipping snapshots based on delta data-related parameters includes;

receiving a snapshot sequence including a plurality of snapshots;

determining a number of delta data chunks between each snapshot in the snapshot sequence;

computing a sum of the numbers of delta data chunks between the snapshots in the snapshot sequence, the delta data chunks comprising new data and modified data and excluding old data that remains the same;

determining a number of delta data chunks between a first snapshot and a last snapshot in the snapshot sequence;

determining whether the number of delta data chunks between the first snapshot and the last snapshot in the snapshot sequence is less than a threshold percentage of the sum of the numbers of delta data chunks between the snapshots in the snapshot sequence; and

in response to determining that the number of delta data chunks between the first snapshot and the last snapshot in the snapshot sequence is less than the threshold percentage, skipping intermediate snapshots in the snapshot sequence and replicating the last snapshot in the snapshot sequence through the snapshot replication process.

2. The computer-implemented method of claim 1, wherein skipping the first snapshot through the snapshot replication process comprises:

selecting a next snapshot incrementally following the first snapshot;

retrieving a creation time of the next snapshot;

computing a time difference between the current time and the creation time of the next snapshot;

determining whether the time difference between the current time and the creation time of the next snapshot is less than the recovery point objective;

in response to determining that the time difference between the current time and the creation time of the next snapshot is less than the recovery point objective, replicating the next snapshot through the snapshot replication process; and

in response to determining that the time difference between the current time and the creation time of the next snapshot is not less than the recovery point objective, skipping the next snapshot through the snapshot replication process.

3. The computer-implemented method of claim 1, wherein the current time comprises a current time when the previously replicated snapshot is replicated.

4. The computer-implemented method of claim 1, wherein each of the snapshots reflects data as it existed on one or more data volumes at a particular point in time.

5. The computer-implemented method of claim 1, wherein one or more of the snapshots is taken in regular intervals.

6. The computer-implemented method of claim 1, wherein one or more of the snapshots is taken under direction of an administrator.

7. The computer-implemented method of claim 1, wherein replicating the first snapshot through the snapshot replication process comprises replicating delta data between the first snapshot and the previously replicated snapshot.

8. The computer-implemented method of claim 1, the computer-implemented method comprising computer-implemented operations for:

providing a storage resource management chart adapted to display information regarding data replication rate.

9. The computer-implemented method of claim 1, wherein the snapshot sequence comprises at least the first snapshot taken at a given time, a second snapshot taken after the first snapshot, and a third snapshot taken after the second snapshot;

and wherein skipping intermediate snapshots in the snapshot sequence and replicating the last snapshot in the snapshot sequence through the snapshot replication process comprises skipping the second snapshot and replicating the third snapshot in the snapshot sequence.

10. The computer-implemented method of claim 1, wherein each of the snapshots comprises a copy of a data volume at a given point in time.

11. The computer-implemented method of claim 1, wherein skipping intermediate snapshots in the snapshot sequence and replicating the last snapshot in the snapshot sequence through the snapshot replication process comprises replicating the delta data between the first snapshot and the last snapshot in the snapshot sequence.

12. The computer-implemented method of claim 1, the computer-implemented method comprising computer-implemented operations for:

providing a storage resource management chart adapted to display information regarding network bandwidth, network traffic, and volume growth.

13. A system for skipping snapshots during a snapshot replication process, the system comprising:

a processor; and

a memory in communication with the processor, the memory having stored therein a time-based replication module and a delta data-based replication module executable by the processor, wherein;

the time-based replication module is configured to

select a first snapshot created subsequently to a previously replicated snapshot, the previously replicated snapshot comprising at least a portion of a snapshot created prior to the first snapshot,

retrieve a creation time of the first snapshot,

compute a time difference between a current time and the creation time of the first snapshot,

determine whether the time difference between the current time and the creation time of the first snapshot is less than a recovery point objective,

in response to determining that the time difference between the current time and the creation time of the first snapshot is less than the recovery point objective, replicate the first snapshot in the snapshot replication process, and

in response to determining that the time difference between the current time and the creation time of the first snapshot is not less than the recovery point objective, skip the first snapshot through the snapshot replication process; and

the delta data-based replication module is configured to

receive a snapshot sequence including a plurality of snapshots,

determine a number of delta data chunks between each snapshot in the snapshot sequence,

compute a sum of the numbers of delta data chunks between the snapshots in the snapshot sequence, the delta data chunks comprising new data and modified data and excluding old data that remains the same,

determine a number of delta data chunks between a first snapshot and a last snapshot in the snapshot sequence,

determine whether the number of delta data chunks between the first snapshot and the last snapshot in the snapshot sequence is less than a threshold percentage of the sum of the numbers of delta data chunks between the snapshots in the snapshot sequence, and

in response to determining that the number of delta data chunks between the first snapshot and the last snapshot in the snapshot sequence is less than the threshold percentage, skip intermediate snapshots in the snapshot sequence and replicate the last snapshot in the snapshot sequence through the snapshot replication process.

14. The system of claim 13, wherein to skip the first snapshot through the snapshot replication process, the time-based replication module is further configured to

select a next snapshot incrementally following the first snapshot,

retrieve a creation time of the next snapshot,

compute a time difference between the current time and the creation time of the next snapshot,

determine whether the time difference between the current time and the creation time of the next snapshot is less than the recovery point objective,

in response to determining that the time difference between the current time and the creation time of the next snapshot is less than the recovery point objective, replicate the next snapshot through the snapshot replication process, and

in response to determining that the time difference between the current time and the creation time of the next snapshot is not less than the recovery point objective, skip the next snapshot through the snapshot replication process.

15. The system of claim 13, wherein the snapshot sequence comprises at least the first snapshot taken at a given time, a second snapshot taken after the first snapshot, and a third snapshot taken after the second snapshot;

and wherein skipping intermediate snapshots in the snapshot sequence and replicating the last snapshot in the snapshot sequence through the snapshot replication process comprises skipping the second snapshot and replicating the third snapshot in the snapshot sequence.

16. The system of claim 13, wherein the current time comprises a current time when the previously replicated snapshot is replicated.