Storage system asynchronous data replication cycle trigger with empty cycle detection

• US 10,310,951 B1
• Filed: 03/22/2016
• Issued: 06/04/2019
• Est. Priority Date: 03/22/2016
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Chen, Xiangping, Meiri, David, Veprinsky, Alexandr, Kucherov, Anton, Love, Philip
• Primary Examiner(s): Pham, Tuan A
• Application Number:
  US15/076,775
• Time in Patent Office: 1,169 Days
• Field of Search: None
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 16/184 implemented as replicated file system
• CPC Class Codes: G06F 16/1844 Management specifically adapted to replicated file systems
• CPC Class Codes: G06F 16/1873 Versioning file systems, temporal file systems, e.g. file system supporting different historic versions of files
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 2201/835 Timestamp
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 2212/261 Storage comprising a plurality of storage devices

Abstract

Described embodiments provide systems and processes for performing a data replication process in a storage system. A current asynchronous replication cycle is initiated at a time-based interval based upon a replication policy of the storage system to replicate data from at least one source device to at least one target device. For the current asynchronous replication cycle, it is determined whether data stored on portions of the source device has changed from a previous asynchronous replication cycle. A new replica of the source device is generated if data stored on the source device has changed from the previous asynchronous replication cycle. The new replica is transferred to the target device. The current asynchronous replication cycle is completed and the replication policy of the storage system is satisfied without generating the new replica if data stored on the source device has not changed from the previous asynchronous replication cycle.

Claims

1. A method for performing data replication in a storage system, the method comprising:

initiating a current asynchronous replication cycle at a time-based interval based upon a replication policy of the storage system, the current asynchronous replication cycle to replicate data from at least one source device that is part of the storage system to at least one target device that is part of the storage system; and

for the current asynchronous replication cycle;

determining whether data stored on portions of the at least one source device has changed from a previous asynchronous replication cycle based on one or more indicators associated with the data;

when the one or more indicators indicate that the data has not changed from the previous asynchronous replication cycle and the replication policy does not require storage of a replica for the current asynchronous replication cycle if the data has not changed, updating a timestamp of a pre-existing replica of the at least one source device that is stored in the at least one target device to satisfy a Recovery Point Objective (RPO) setting of the storage system without overwriting the pre-existing replica; and

when the one or more indicators indicate that the data has not changed from the previous asynchronous replication cycle and the replication policy requires storage of a replica for the current asynchronous replication cycle if the data has not changed, generating a new replica of the at least one source device and transferring the new replica to the at least one target device,

wherein each of the indicators is associated with a different portion of the source device, and the one or more indicators are stored in a bitmap associated with the source device.

2. The method of claim 1, further comprising, after completing the current asynchronous replication cycle, starting a next asynchronous replication cycle.

3. The method of claim 1, further comprising, when the one or more indicators indicate that the data has changed from the previous asynchronous replication cycle, generating a new replica of the at least one source device and transferring the new replica to the at least one target device.

4. The method of claim 3, wherein determining whether the data has changed includes determining whether the one or more indicators are set.

5. The method of claim 4, further comprising, after transferring the new replica to at least one target device, clearing the one or more indicators.

6. The method of claim 1, wherein the source device includes at least one solid-state drive (SSD) and each portion of the source device includes a different block of the SSD.

7. A storage system comprising:

at least one target device;

at least one source device;

a processor; and

a memory storing computer program code that when executed on the processor causes the processor to execute a data replication process associated with the at least one source device and the at least one target device by performing the operations of;

initiating a current asynchronous replication cycle at a time-based interval based upon a replication policy of the storage system; and

for the current asynchronous replication cycle;

determining whether data stored on portions of the at least one source device has changed from a previous asynchronous replication cycle based on one or more indicators associated with the data;

when the one or more indicators indicate that the data from the at least one source device has not changed from the previous asynchronous replication cycle and the replication policy does not require storage of a replica for the current asynchronous replication cycle if the data has not changed, updating a timestamp of a pre-existing replica of the at least one source device that is stored in the at least one target device to satisfy a Recovery Point Objective (RPO) setting of the storage system without overwriting the pre-existing replica; and

when the one or more indicators indicate that the data from the at least one source device has not changed from the previous asynchronous replication cycle and the replication policy requires storage of a replica for the current asynchronous replication cycle if the data has not changed, generating a new replica of the at least one source device and transferring the new replica to the at least one target device,

wherein each of the indicators is associated with a different portion of the source device, and the one or more indicators are stored in a bitmap associated with the source device.

8. The system of claim 7, wherein the memory stores computer program code that when executed on the processor causes the processor to further perform the operation of, when the one or more indicators indicate that the data has changed from the previous asynchronous replication cycle, generating a new replica of the at least one source device and transferring the new replica to the at least one target device.

9. The system of claim 8, wherein determining whether the data has changed includes determining whether the one or more indicators are set.

10. The system of claim 9, wherein the memory stores computer program code that when executed on the processor causes the processor to further perform the operation of, after transferring the new replica to at least one target device, clearing the one or more indicators.

11. A computer program product including a non-transitory computer readable storage medium having computer program code encoded thereon that when executed on a processor, cause the processor to perform the operations of:

initiating a current asynchronous replication cycle at a time-based interval based upon a replication policy of a storage system, the current asynchronous replication cycle to replicate data from at least one source device that is part of the storage system to at least one target device that is part of the storage system; and

for the current asynchronous replication cycle;

determining whether data stored on portions of the at least one source device has changed from a previous asynchronous replication cycle based on one or more indicators associated with the data;

when the one or more indicators indicate that the data has not changed from the previous asynchronous replication cycle and the replication policy does not require storage of a replica for the current asynchronous replication cycle if the data has not changed, updating a timestamp of a pre-existing replica of the at least one source device that is stored in the at least one target device to satisfy a Recovery Point Objective (RPO) setting of the storage system without overwriting the pre-existing replica; and

when the one or more indicators indicate that the data has not changed from the previous asynchronous replication cycle and the replication policy requires storage of a replica for the current asynchronous replication cycle if the data has not changed, generating a new replica of the at least one source device and transferring the new replica to the at least one target device,

wherein each of the indicators is associated with a different portion of the source device, and the one or more indicators are stored in a bitmap associated with the source device.