Synchronous replication

• US 10,496,320 B2
• Filed: 12/28/2015
• Issued: 12/03/2019
• Est. Priority Date: 12/28/2015
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Eisler, Michael Robin, Rao, Santosh Ananth, Kaushik, Akhil, Mu, Yuedong
• Primary Examiner(s): Leibovich, Yair
• Application Number:
  US14/980,526
• Publication Number:
  US 20170185306A1
• Time in Patent Office: 1,436 Days
• Field of Search: 714 621
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2076 Synchronous techniques
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• 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]

Abstract

One or more techniques and/or computing devices are provided for synchronous replication. For example, synchronous replication relationships are established between a first storage object (e.g., a file, a logical unit number (LUN), a consistency group, etc.), hosted by a first storage controller, and a plurality of replication storage objects hosted by other storage controllers. In this way, a write operation to the first storage object is implemented in parallel upon the first storage object and the replication storage objects in a synchronous manner, such as using a zero-copy operation to reduce overhead otherwise introduced by performing copy operations. Reconciliation is performed in response to a failure so that the first storage object and the replication storage objects comprise consistent data. Failed write operations and replication write operations are retried, while enforcing a single write semantic. Dependent write order consistency is enforced for dependent write operations, such as overlapping write operations.

Claims

1. A method comprising:

receiving a replication operation, corresponding to a replication of a write operation received by a first device for implementation upon a storage object hosted by the first device, for implementation upon a replication storage object hosted by a second device;

receiving a retry replication operation, before receiving the replication operation, corresponding to a retry of the replication operation triggered in response to a lifecycle of the write operation indicating that the replication operation has not been implemented by the second device;

implementing the retry replication operation upon the replication storage object; and

avoiding implementing the replication operation based upon successful implementation of the retry replication operation.

2. The method of claim 1, comprising:

performing a reconciliation between the storage object and the replication storage object based upon the first device experiencing a failure, wherein content, targeted by an operation associated with the failure, is read from the storage object and written into the replication storage object before a client acknowledgment for the operation is sent.

3. The method of claim 2, comprising:

utilizing consistency points to perform a data integrity validation to flag data corruption based upon successfully writing the content so that data within the storage object and the replication storage object have data symmetry.

4. The method of claim 2, comprising:

utilizing consistency points to perform a data integrity validation to flag data loss issues based upon successfully writing the content so that data within the storage object and the replication storage object have data symmetry.

5. The method of claim 1, comprising:

utilizing an inflight time tracking module to track a lifecycle of the write operation.

6. The method of claim 1, comprising:

withholding a client acknowledgement that the write operation is complete until the write operation and the replication operation are complete.

7. The method of claim 1, comprising:

enforcing a single write sematic by disregarding the replication operation based upon the retry replication operation being successfully performed.

8. The method of claim 1, comprising:

enforcing a dependent write order consistency for the replication operation and a second replication operation based upon the second replication operation and the replication operation having a dependency.

9. The method of claim 8, comprising:

determining that the second replication operation and the replication operation have the dependency based upon the replication operation and the second replication operation overlapping a same region that is to be modified.

10. The method of claim 8, wherein the enforcing a dependent write order consistency comprises:

serially implementing the replication operation and the second replication operation.

11. The method of claim 1, wherein the implementing comprises:

performing a zero-copy operation upon the first device using a data reference in place of copying data associated with the replication operation.

12. The method of claim 1, comprising:

implementing a replication metadata operation upon the first device.

13. The method of claim 12, wherein the replication metadata operation comprises an application consistency point creation operation.

14. The method of claim 1, wherein the storage object is exposed with read and write access and the replication storage object is exposed with read only access with a write access option when a failover is performed.

15. The method of claim 1, wherein the first device and the second device are maintained within a cloud storage environment.

16. The method of claim 1, wherein the first device is hosted within a storage environment accessible to client devices and the second device is hosted within a cloud storage environment accessible to the storage environment.

17. The method of claim 1, comprising:

performing load balancing for access to the replication storage object.

18. A non-transitory machine readable medium having stored thereon machine executable code which when executed by a machine, causes the machine to:

receive a replication operation, corresponding to a replication of a write operation received by a first device for implementation upon a storage object hosted by the first device, for implementation upon a replication storage object hosted by a second device;

receive a retry replication operation, before receiving the replication operation, corresponding to a retry of the replication operation triggered in response to a lifecycle of the write operation indicating that the replication operation has not been implemented by the second device;

implement the retry replication operation upon the replication storage object; and

avoid implementing the replication operation based upon successful implementation of the retry replication operation.

19. The non-transitory machine readable medium of claim 18, wherein the machine executable code causes the machine to:

utilize an inflight time tracking module to track a lifecycle of the write operation.