Hyper-V Cluster VM Live Migration Failing

Question

Good morning!

I have recently experience some issues with VM Live Migration error 21502. I have checked most if not all of past post on this error but none worked.

We have say 10 Hypervisors in a Cluster. The problem only appeared on 2 of them say HV1 and HV8. The VMs on these 2 Hypervisors can only Live Migrate to each other. The VMs on the rest of the Hypervisors can Live Migrate to any of the Hypervisors including the 2 with issues.

The settings are all the same and hardware are also the same. Virtual Switch names are also the same. System Resources are sufficient and SMB3 are not used on any of the Hypervisors.

Can anyone point me a direction as to why this is happening?

Appreciate any comment and advise on this issue greatly appreciated.

Thank you and best regards.

Ronald

Answer 1

Hi,
Since some of the nodes can successfully migrate to other nodes, there should not be any problem with your configuration.
According to the error code 21502, there might be some problem with the network. Before live migration, you need to go to the destination node and manually set the virtual switch ready. Would you change another virtual switch and try again?
If the problem exists, please check the event log of your cluster. In event viewer as below:

For your reference:
https://learn.microsoft.com/en-us/troubleshoot/windows-server/virtualization/troubleshoot-live-migration-issues

Thanks for your time.
Best regards,
Danny

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Answer 2

Hi! Danny,

Thanks for replying to my question.

The logs has been checked repeatedly but they are too generic and does not point to an area we have not looked at.

We have also checked the vSwitch but nothing is amiss.

You see VMs on hypervisor 1 & 8 can only live migrate among themselves. VMs on other hypervisor like 5 can live migrate to 1 and 8 and also other hypervisors and back.

Is there another area we should look into?

Appreciate any advise.

Thank you and best regards.
Ronald

Answer 3

Hi Ronald,

Here’re my suggestions:

1. In failover cluster manager, try viewing validation report, see if there’s any network or configuration problem:

2. Creating a new VM on HV1 and HV8, try configuring them with and without virtual switches just like the other nodes, and see if live migration works;
3. If live migration doesn’t work, try quick migration;
4. Copy the vhds of those 2 VMs, use them to create new VMs and see if live migration works.

Thanks for your time.

Best regards,

Danny

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Answer 4

Good afternoon! Danny,

My apology for the delay in reply.

I am still awaiting for an opportunity to perform that test you recommended. Will update again once i have any findings.

Thank you and best regards.
Ronald