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Hello,
We have a 4 node 2019 failover cluster running Hyper-V VMs.
We have started seeing that one of our networks is showing as "Partitioned" as below:
The nodes can ping each other on that network, port 3343 is open, and there are no firewalls in between the nodes.
The cluster is currently operating correctly as far as I can see, but I'd like to resolve this error to prevent any possible issues.
Can anyone advise how to correct this?
Thanks
James
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After I disabled and re-enabled cluster and client traffic on this network, even though I made no changes to host or switch side network config, the network status restored to normal.
I'll be keeping an eye on it to ensure stable, but this does seem to have resolved the issue, and doesn't seem to have been config related.
Many thanks
James
Hello @James Edmonds ,
Thank you for your question.
Your problem is most often caused by an incorrect network configuration, or other possible ones are caused by NIC not having been installed correctly, if the third party solution listed below does not work, try removing hidden devices (adapters) in device manager, update the server firmware to the latest then monitor this issue again.
Use the link in the topic below that has a problem similar to yours, I believe it will be useful for you:
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If the answer is helpful, please vote positively and accept as an answer.
Thanks for your answer.
I can't see what network config issue would be present, as it has only recently appeared as an error and has been functional for a couple of years until now, and we have not made any network changes.
Is there a way to determine what it thinks is the issue, as the validation report suggests that nodes cannot connect to each other using IPs on that subnet over port 3343 UDP, which does not appear to be true.
In my screenshot, the BASE-T network is used by the nodes to access storage boxes. I suspect it can also be allowed to do cluster traffic.
I saw another suggestion that was to disable cluster traffic on the partitioned network to see if that removes the error.
My query is, as the window mentions client traffic, what exactly is this?
If I disable cluster traffic, it also disables client traffic. Cluster traffic I understand, but does client traffic refer to clients access the failover cluster manager itself, or does it refer to the network access for VMs running in the cluster.
If anything, I would want the BASE-T network to be cluster only, and the cluster network to be client only, as I cannot access the cluster via the storage network as it is a totally isolated network.
Many thanks.
James
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In Failover Cluster Manager:
This space shows the hosts and adapters that have presence in this network by assigned IP address and netmask. Unfortunately, ping is not terribly useful in this case.
I have only seen it happen once, and that appeared to be because my physical switch and the Hyper-V virtual switch could no longer agree on VLAN frames. I only did cursory troubleshooting and did not discover anything. I believe the problem lies with the physical switch, as I have dozens of similar configurations and only the one displayed the problem. Removing the virtual adapters from their VLANs and relying on layer 3 isolation worked for me.
I'm not sure what clues to look for?
All adapters show unreachable with no other info, and the critical events window is blank for them all:
Each of these adapters is a Windows Server NIC team in switch independent mode, and there is no switch side port config related to these Teams, so I don't see how the switch can be at fault.
Everything seems to be working, so could it just be a UI error?
Cheers
James
I always say to triple-check the IPs and netmasks on every node. I also kill IPv6 because, despite all sorts of public yelling to the contrary, it never seems to do anything positive for clustering.
I don't believe that it's just a UI thing because the UI sits directly atop Failover Clustering's WMI interface with nothing inbetween. I guess there's a possible bug in the lower layer, but that seems improbable. If it's getting to the WMI tools as an unreachable status, then the cluster is treating it as unreachable.
My next plan was to use Wireshark scoped to the connection between a couple of the troubled adapters to see if that yields any clues. I never got that far myself.
Everything still looks ok to be.
What is the effect of disabling cluster and client traffic on that network?
I assume cluster traffic is just in relation to heartbeats and migrations between hosts?
What is client traffic? Will disabling client traffic stop me from accessing the host itself via that network, impact the Hyper-V vSwitch (which is what this network sits atop of), disrupt VM traffic or just access to the cluster service via that network?
Many thanks.
James.
When the network shows as partitioned, it's already excluded from cluster and client traffic.
A failover cluster of Hyper-V hosts doesn't expose any client connection points on its cluster networks so the only thing you can possibly lose is inter-node communication. In the state shown in your screenshot, you only have one network that can carry inter-node traffic so it will have no backup path for carrying heartbeat information, node state updates, or CSV traffic if any.
Thanks.
In which case I will look to disable and re-enable the network for those purposes to see if it recovers.