Synchronization cache seeding

• US 10,496,676 B2
• Filed: 08/29/2014
• Issued: 12/03/2019
• Est. Priority Date: 08/29/2014
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Mu, Yuedong, Ngan, Ching-Yuk Paul, Sundararajan, Manoj V
• Primary Examiner(s): Savla, Arpan P.
• Assistant Examiner(s): Davanlou, Soheila (Gina)
• Application Number:
  US14/473,081
• Publication Number:
  US 20160063083A1
• Time in Patent Office: 1,922 Days
• Field of Search: None
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency
• CPC Class Codes: H04L 47/828 Allocation of resources per group of connections, e.g. per group of users
• CPC Class Codes: H04L 65/40 Support for services or applications
• CPC Class Codes: H04L 67/1078 Resource delivery mechanisms
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

Synchronization metadata is read from non-volatile storage. The synchronization metadata comprises indications of one or more synchronization targets. A synchronization target is a node of a clustered storage system. A synchronization cache is populated with the synchronization metadata. After populating the synchronization cache with at least a portion of the synchronization metadata, a connection to a network is established. After the connection to the network is established, a connection to a first of the one or more synchronization targets is established.

Claims

1. A method comprising:

reading synchronization metadata when booting a first node into an operational state to identify a synchronization target as a second node;

loading the synchronization metadata into a cache of the first node, wherein the synchronization metadata maps files to replication-critical consistency groups, replication-non-critical consistency groups, and no consistency group;

loading a networking subsystem into a functional state, to establish a connection from the first node to the second node using the synchronization metadata, based upon the synchronization metadata being loaded into the cache;

receiving an operation from a client to modify a file at the first node, wherein the operation is executed upon the file at the first node and is replicated to the second node for execution upon the synchronization target;

transmitting an acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-critical consistency group and execution of the operation at the first node and replication of the operation at second node successfully completing; and

transmitting the acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-non-critical consistency group and execution of the operation at the first node successfully completing irrespective of whether the replication to the second node has completed.

2. The method of claim 1, comprising:

updating the synchronization metadata to identify the synchronization target as a third node based upon a determination that the synchronization target was migrated to the third node.

3. The method of claim 1, wherein the connection is established when booting the first node into the operational state.

4. The method of claim 1, wherein the reading comprises:

reading the synchronization metadata from sequential locations from storage.

5. The method of claim 1, comprising:

executing the operation upon the file without replicating the operation to the second node based upon the synchronization metadata mapping the file to no consistency group.

6. The method of claim 1, comprising:

populating the synchronization metadata with a first structure mapping nodes that are consistency group endpoints to synchronization targets located at corresponding nodes and a second structure listing individual synchronization targets that have consistency group endpoints.

7. The method of claim 6, comprising:

transmitting the acknowledgment, where the synchronization metadata maps the file to the replication-critical consistency group, based upon receiving a replication complete acknowledgment from the second node that replication of the operation completed.

8. A non-transitory machine readable medium comprising instructions for performing a method, which when executed by a machine, causes the machine to:

read synchronization metadata when booting a first node into an operational state to identify a synchronization target as a second node;

load the synchronization metadata into a cache of the first node, wherein the synchronization metadata maps files to replication-critical consistency groups, replication-non-critical consistency groups, and no consistency group;

load a networking subsystem into a functional state, to establish a connection from the first node to the second node using the synchronization metadata, based upon the synchronization metadata being loaded into the cache;

receive an operation from a client to modify a file at the first node, wherein the operation is executed upon the file at the first node and is replicated to the second node for execution upon the synchronization target;

transmit an acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-critical consistency group and execution of the operation at the first node and replication of the operation at second node successfully completing; and

transmit the acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-non-critical consistency group and execution of the operation at the first node successfully completing irrespective of whether the replication to the second node has completed.

9. The non-transitory machine readable medium of claim 8, wherein the instructions cause the machine to:

update the synchronization metadata to identify the synchronization target as a third node based upon a determination that the synchronization target was migrated to the third node.

10. The non-transitory machine readable medium of claim 8, wherein the connection is established when booting the first node into an operational state.

11. The non-transitory machine readable medium of claim 8, wherein the reading comprises:

reading the synchronization metadata from sequential locations in storage.

12. The non-transitory machine readable medium of claim 8, wherein the cache is implemented within a non-volatile random access memory (NVRAM).

13. The non-transitory machine readable medium of claim 8, wherein the reading comprises:

reading the synchronization metadata from multiple non-sequential locations in storage.

14. The non-transitory machine readable medium of claim 8, wherein the instructions cause the machine to:

populate the synchronization metadata with synchronization target status information of synchronization targets located at consistency group endpoints.

15. The non-transitory machine readable medium of claim 14, wherein the synchronization metadata specifies what synchronization targets contain consistency group endpoints of a consistency group.

16. The non-transitory machine readable medium of claim 8, wherein the synchronization metadata specifies synchronization targets for a replication-non-critical consistency group and synchronization targets for a replication critical consistency group.

17. A computing device comprising:

a memory comprising machine executable code; and

a processor coupled to the memory, the processor configured to execute the machine executable code to cause the processor to;

read synchronization metadata when booting a first node into an operational state to identify a synchronization target as a second node;

load the synchronization metadata into a cache of the first node, wherein the synchronization metadata maps files to replication-critical consistency groups, replication-non-critical consistency groups, and no consistency group;

load a networking subsystem into a functional state, to establish a connection from the first node to the second node using the synchronization metadata, based upon the synchronization metadata being loaded into the cache;

receive an operation from a client to modify a file at the first node, wherein the operation is executed upon the file at the first node and is replicated to the second node for execution upon the synchronization target;

transmit an acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-critical consistency group and execution of the operation at the first node and replication of the operation at second node successfully completing; and

transmit the acknowledgement to the client that the operation is complete based upon the synchronization metadata mapping the file to a replication-non-critical consistency group and execution of the operation at the first node successfully completing irrespective of whether the replication to the second node has completed.

18. The computing device of claim 17, wherein the machine executable code causes the processor to:

determine, over the connection with the second node, as to whether the synchronization metadata stale.

19. The computing device of claim 17, wherein the machine executable code causes the processor to:

update the synchronization metadata to identify the synchronization target as a third node based upon a determination that the synchronization target was migrated to the third node.

20. The computing device of claim 17, wherein the machine executable code causes the processor to:

update the synchronization metadata within the cache to identify the synchronization target as a third node based upon a determination that the synchronization target was migrated to the third node.