I'd like to share the following experience with you.
We've recently upgraded 2 FAS3240 fabric-attachedMetrocluster Nodes (HA Pair) running 8.0.2 7mode and as well 2 newly arrived FAS3250 fabric-attachedMetrocluster Nodes (running 8.1.x 7mode) to DOT 8.2.1 (7mode).
We've experienced the following issue during the pre-production failover tests of the new system:
Even if the MetroCluster Feature was licensed under 8.1 release correctly, the cf.remote_syncmirror.enable option for this feature to work is not setup correctly by the update procedure. We had to do this manually!
That means, if you lose one complete side of the fabric attached HA Pair, the command cf forcetakeover -d fails with the following message:
cf: forcetakeover -d cannot be performed because remote synchronous mirroring is not enabled
for the MetroCluster Feature to work correctly you have to check the following 2 options:
on (same value required in local+partner)
It's easier to check/set this options while both nodes are healthy 🙂