SnapMirror and Node Upgrade Order
tl-dr ( how do I upgrade ONTAP when clusters are both a source and a destination for SnapMirrors. Instructions say destination first. Whaaa? )
We are planning upgrade from 8.3.1 to 9.1P5 . The AutoSupport Upgrade Advisor Plan generated for this task, gives the following advice for suspending SnapMirror replication, and the correct order in which to upgrade the Peers of the SnapMirror relationship:
Suspending SnapMirror operations
WARNING
Cluster mycluster2 is running SnapMirror.
To prevent SnapMirror transfers from failing, you must suspend SnapMirror operations and upgrade destination nodes before upgrading source nodes.
(i) Suspend SnapMirror transfers for a destination volume
(ii) Upgrade the node that contains the destination volume
(iii) Upgrade the node that contains the source volume
(iv) Resume the SnapMirror transfers for the destination volume.
Note: SnapMirror transfers for all other destination volumes can continue while the nodes that contain the original destination and source volumes are upgraded.
Our problem is that mycluster2 and the Cluster it is SnapMirroring to, mycluster1 have Volumes where SnapMirror replication is going in both directions:
mycluster1 - svm1 - vol1 SnapMirror--> mycluster2 - svm2 - vol1_dr
mycluster1 - svm1 - vol2_dr SnapMirror<-- mycluster2 - svm2 - vol2
So, the question is, which cluster should I upgrade to 9.1P5 first? Each cluster contains both source, and destination volumes.