What happens during a spanning tree calculation? All ports goes into a blocked state. How could that be an issue for Hyper-V?
I will tell you 🙂
If you have a Hyper-V cluster connected to a large core network and you have a spanning tree calculation and not rapid spanning tree enabled the heartbeat will be in a state that Hyper-V can not handle. The port will be up and if you have NIC-teaming on the team will not see that the NIC is unavailable and will keep try to run the heartbeat on the blocked NIC. this will result in a cluster failure where the Hyper-V host thinks it lost its friends and kicks itself out of the cluster. The sad part about this is that the same will happens to the other hosts as well. The result? a catastrophe. How to solve this? We have done a couple of precautions.
- Keep the Heartbeat network separated from the main core.
- Enable rapid spanning tree