Synchronous replication for synchronous mirror copy guarantee
Techniques are provided for synchronous replication for synchronous mirror copy guarantee. A file system dependent technique for synchronous mirror copy guarantee is provided by overriding default behavior of a persistent fence so that the persistent fence is activated to block operations targeting a storage object having a synchronous replication relationship based upon the synchronous replication relationship being out of sync. The default behavior of the persistent fence is overridden to allow operations to be executed upon the storage object based upon the synchronous replication relationship being in sync. A file system independent technique for synchronous mirror copy guarantee is provided by intercepting operations before the operations are received by a file system. The operations are selectively forwarded to the file system or not based upon a state of a synchronous replication relationship.
1. A method comprising:
maintaining a synchronous replication relationship between a first storage object and a second storage object, wherein an operation is acknowledged based upon the operation being executed upon the first storage object and replicated to the second storage object;
overriding default behavior of a persistent fence provided by a file system for the first storage object, wherein the overriding comprises modifying behavior of the persistent fence to allow data management operations that access an existing snapshot and block data management operations that access an active file system when the synchronous replication relationship is out of sync;
activating the persistent fence to block incoming operations based upon a determination that the synchronous replication relationship is out of sync; and
deactivating the persistent fence to allow incoming operations to be executed and replicated based upon a determination that the synchronous replication relationship is in sync.
2. The method of claim 1 , wherein the default behavior corresponds to blocking all incoming operations targeting the first storage object irrespective of whether the synchronous replication relationship is in sync.
3. The method of claim 1 , comprising:
modifying behavior of the persistent fence to block modify operations and allow read operations when the synchronous replication relationship is out of sync.
4. The method of claim 1 , wherein the activating comprises:
activate the persistent fence to block modify operations and read operations when the synchronous replication relationship is out of sync.
5. The method of claim 1 , comprising grouping incoming operations into a read only category and a write category.
6. The method of claim 5 , comprising:
activating the persistent fence to block incoming operations grouped into the write category when the synchronous replication relationship is out of sync.
7. The method of claim 6 , comprising:
modifying behavior of the persistent fence to allow incoming operations grouped into the read only category when the synchronous replication relationship is out of sync.
8. The method of claim 1 , comprising:
bringing the synchronous replication relationship in sync by invoking a file system application programming interface (API) to deactivate the persistent fence.
9. The method of claim 1 , comprising:
bringing the synchronous replication relationship out of sync by sending operations to the file system with an indicator to activate the persistent fence.
10. The method of claim 1 , comprising:
bringing the synchronous replication relationship out of sync by asynchronously invoking a file system application programming interface (API) to activate the persistent fence.
11. The method of claim 1 , comprising:
activating the persistent fence to block the data management operations that access the active file system when the synchronous replication relationship is out of sync.
12. The method of claim 1 , wherein the activating comprises:
deactivating the persistent fence to allow the data management operations that access the existing snapshot when the synchronous replication relationship is out of sync.
13. The method of claim 1 , comprising:
deactivating the persistent fence to perform a data mobility operation comprising a snapshot creation operation to create a snapshot for a cutover workflow of the data mobility operation to move the first storage object, wherein the fence is reactivated after the data mobility operation.
14. The method of claim 1 , comprising:
performing a data mobility operation to move the second storage object.
15. A non-transitory machine readable medium comprising instructions for performing a method, which when executed by a machine, causes the machine to:
intercept operations targeting a first storage object having a synchronous replication relationship with a second storage object, wherein an operation is acknowledged based upon the operation being executed upon the first storage object and replicated to the second storage object;
forward the operations to a file system for execution upon the first storage object and replication to the second storage object based upon the synchronous replication relationship being in sync;
block the operations from being forwarded to the file system based upon the synchronous replication relationship being out of sync; and
forward data management operations to the file system that access an existing snapshot and block data management operations that access an active file system when the synchronous replication relationship is out of sync.
16. The non-transitory machine readable medium of claim 15 , wherein the instructions cause the machine to:
control an I/O filter driver, executed above the file system within a storage stack, to selectively forward and block operations based upon a state of the synchronous replication relationship.
17. The non-transitory machine readable medium of claim 15 , wherein the instructions cause the machine to:
loading a splitter hosted within a boot time module that is loaded prior to the file system being loaded, wherein the splitter is controlled to selectively forward and block operations based upon a state of the synchronous replication relationship.
18. The non-transitory machine readable medium of claim 15 , wherein the instructions cause the machine to:
block read operations and write operations from being forwarded to the file system based upon the synchronous replication relationship being out of sync.
19. The non-transitory machine readable medium of claim 15 , wherein the instructions cause the machine to:
allow read operations and block write operations from being forwarded to the file system based upon the synchronous replication relationship being out of sync.
20. A computing device comprising:
a memory comprising machine executable code for performing a method; and
a processor coupled to the memory, the processor configured to execute the machine executable code to cause the processor to:
maintain a synchronous replication relationship between a first storage object and a second storage object, wherein an operation is acknowledged based upon the operation being executed upon the first storage object and replicated to the second storage object;
override default behavior of a persistent fence provided by a file system for the first storage object, comprising modifying behavior of the persistent fence to allow data management operations that access an existing snapshot and block data management operations that access an active file system when the synchronous replication relationship is out of;
activate the persistent fence to block incoming operations based upon a determination that the synchronous replication relationship is out of sync; and
deactivate the persistent fence to allow incoming operations to be executed and replicated based upon a determination that the synchronous replication relationship is in sync.