Snapmirror Reverse Resync ONTP 9.11

[BenBrazil]

Hi,

What is the preferred method of performing a Snapmirror Reverse Resync after a DR scenario where we want to keep the data that has been written to the volumes?

I have two Clusters - Cluster1 in the Primary DC and Cluster2 in the Secondary DC where under normal circumstances, the volumes on Cluster2 are the Snapmirror Destinations.

In a DR scenario all Snapmirror volumes in Cluster2 are now Broken-Off, read /write and we have written data to the volumes in Cluster2.

I've read the following process on https://www.flackbox.com/netapp-snapmirror-data-protection (possibly the old way to do it) where the snapmirror is deleted from Cluster2, recreated on Cluster1 with Cluster2 as the source and Cluster1 as the destination and then resynced. Once the sync is done, the Snapmirror is deleted from Cluster1 and then recreated back on Cluster2, resulting in Cluster2 now being the Snapmirror destination. 

Is this no longer the recommended method to follow?

The second process that I have read is once the Snapmirror is broken-off on Cluster2, a Snapmirror resync is performed on Cluster1 making Cluster2 the Source and Cluster1 the destination.

The process is discussed here: https://vmstorageguy.wordpress.com/2018/01/07/how-to-netapp-ontap-reverse-snapmirror-cdot/

Is this now the recommended way to run the reverse resync? 

I am aware that the resync can be done in System Manager, but will be performing via the CLI.

Thanks,

Ben

[Ontapforrum · Accepted solution]

It depends on the scenario, if the snapmirror-relationship is deleted, then I have no choice but to re-create the relationship and resync. If it's not deleted, then I would rather use the common snapshot to reverse resync faster (2nd method).

If you are running ONTAP 9.8, just follow the steps in the links below (via system manager). But, you can also do it via CLI as you prefer.

Reverse Resynchronizing a Protection Relationship:
https://docs.netapp.com/us-en/ontap/task_dp_reverse_resynch_a_destination_vm.html

Reverse Resync dialog box (netapp.com)

Outline of steps to reactivate a source SVM and flip-resync:
https://mysupport.netapp.com/site/article?lang=en&page=%2FAdvice_and_Troubleshooting%2FData_Protection_and_Security%2FSnapMirror%2FHow_to_perform_a_%2...

How to run SnapMirror reverse resync with "-quick-resync" parameter (applies to XDP only)
https://kb.netapp.com/Advice_and_Troubleshooting/Data_Protection_and_Security/SnapMirror/How_to_run_SnapMirror_reverse_resync_with_%22-quick-resync%22...

Please note - resync requires "common SnapMirror Snapshot" to exists on both source and destination.

Related:
https://kb.netapp.com/Advice_and_Troubleshooting/Data_Infrastructure_Management/ONTAP_System_Manager/Reverse_Resync_fails_in_System_Manager_when_peer_...

[BenBrazil]

Thanks for your reply. I've tested using the method as described by the vmstorageguy article and all worked successfully.

Thanks,

Ben