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Citrix XenServer internal error - Fix it Now ?

Sometimes after failing the operation to Move VM, Copy VM, or Export VM on a Virtual Machine (VM) it will not start. Furthermore, it ends up with an Internal error.

The Control Domain connection can be seen on the disk by selecting the Storage Repository Object on the Left Pane of the XenCenter, by browsing to the Storage Tab. 

In the VM column, the Disk (VDI) is seen being attached to both the Control Domain of a XenServer and the VM itself.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to fix Server Internal errors.


What triggers Citrix XenServer internal error ?

This error occurs when the Control Domain on XenServer that runs VM, attaches Virtual Disk Image (VDI) of VM to Control Domain.

  • The Control Domain uses this disk to perform the operations that have been initiated on the VM.
  • If any operation fails, the VDI will still have an attachment to the control domain through a Virtual Block Device. We have to destroy the connection.
  • The Control Domain connection can be seen on the disk by selecting the Storage Repository Object.
  • This can be seen on the Left Pane of the XenCenter, in the Storage Tab.



How to resolve Citrix XenServer internal error ?

We can use the following steps to fix this error:

1. First, we need to open the Console to the XenServer that is hosting the VM.

2. And run the following command:

#list_domains

3. Then we have to copy the UUID corresponding to id=0.

This is the UUID of the Control Domain.

4. After that we need to run the following command to obtain the UUID of the VBD (Virtual Block Device) object linking the Control Domain:

#xe vbd-list vm-uuid=<uuid of the Control Domain>

5. Finally, we need to run the following commands to unplug and destroy the VBD:

#xe vbd-unplug uuid=<uuid of the vbd>
#xe vbd-destroy uuid=<uuid of the vbd>


[Still stuck with Server errors? We can help you. ]


Conclusion

This article covers methods to fix Citrix XenServer internal error for our customers. This error occurs because the Control Domain (Dom0) on the XenServer which runs the VM, attaches the Virtual Disk Image (VDI) of the VM to Control Domain. 

This attached disk is then operated by the Control Domain to perform the operations which has been initiated on the VM. As the operation fails, the VDI is still attached to the control domain through a Virtual Block Device (VBD) connection that needs to be destroyed.