Archive for category VMM 2012 R2

Adding existing Hyper-V cluster to VMM 2012 R2


I have just stumbled across an article in regards to moving Hyper-V cluster with production  load to a VMM 2012/2012 R2 environment.

VMM will (as part of adding the new cluster) add MIPO device list to each of the hosts participating in the cluster, which would cause a loss of connectivity to storage.

Edit: After doing a bit of investigation to MPIO, things to bare in mind:

  1. if you are adding an existing Hyper-V cluster to VMM and one or more of your hosts failed to join, drain one of those ‘Pending’ nodes and work on it separately. This would avoid any impact on production load.
  2. Remove any MPIO settings under Control Panel -MPIO as shown below: (Don’t reboot).

mpio1    3. Try adding the Hyper-V host to VMM.

You could query connected SAN (using mpclaim -e) and display it as vendor-product id strings which you could add via the MPIO GUI.


As you can see there are spaces added to the end of the string to make it compatible. This is necessary, and adding to VMM would fail otherwise.


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Error 20400 – VMM 2012 R2

Error (20400)

1 parallel subtasks failed during execution.

 Error (2605)

Unable to connect to the VMM database because of a general database failure.

SQL error code: 547

Recommended Action

Ensure that the SQL Server is running and configured correctly, then try the operation again.

We have received this error while removing a Hyper-v cluster out of VMM 2012 R2. Even trying to reinstall VMM agent fails manually. Trying both Remove-SCVMHost and Remove-SCVMHostCluster with -Force also failed miserably!

I have found a good article that takes you through these steps of removing hosts/cluster from the DB end, just make sure you have a backup before you start.

You can find the article here.

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