Hyper-V Live Migration fails on Windows Server 2008 R2 with Event IDs 21203 and 21125

Applies to: Microsoft Hyper-V Server 2008 R2Windows Server 2008 R2 DatacenterWindows Server 2008 R2 Enterprise More


When you perform a live migration of a Hyper-V virtual machine on Windows Server 2008 R2, the live migration may fail and the virtual machine will have a status of Online (Migration attempt failed).

On the destination node, the following events will be logged in the Microsoft-Windows-Hyper-V-High-Availability/Admin event log:

Log Name:      Microsoft-Windows-Hyper-V-High-Availability-Admin
Source:        Microsoft-Windows-Hyper-V-High-Availability
Event ID:      21203
Failed to create virtual network switch port '4825deff-6f69-45fd-92f2-3d344f0b95b2'. (HRESULT 0x80070490)

Log Name:      Microsoft-Windows-Hyper-V-High-Availability-Admin
Source:        Microsoft-Windows-Hyper-V-High-Availability
Event ID:      21125
Configuration setup for live migration failed on the destination node. Make sure that name of the virtual network is the same on the source and destination nodes, and try the live migration again.


This issue occurs if the virtual network name is not the same between the source and destination nodes.


To resolve this issue, perform the following steps:

1.     Open the Hyper-V Manager console on the source and destination nodes.
2.     Select Virtual Network Manager.
3.     Verify that the virtual network names match between the source and destination nodes.
4.     Click OK to close the Virtual Network Manager window.
5.     Right-click on the virtual machine on the source node and select Settings.
6.     Verify that the virtual machine is configured to use the correct virtual network.
7.     Click OK to close the Virtual Machine Settings window.
8.     Close the Hyper-V Manager console on the source and destination nodes.
9.     Open the Failover Cluster Manager console on the source node.
10.   Expand Services and Applications and then select the Virtual Machine.
11.   In the Actions pane, click More Actions, and then click Refresh virtual machine configuration.
12.   Perform a live migration of the virtual machine to the destination node.

More Information

For more information on Hyper-V, visit the following Microsoft web site: http://technet.microsoft.com/en-us/library/cc753637(WS.10).aspx