Careful with Live Storage Migration and ODX

ODX – Offloaded Data Transfers is a technology developed by Microsoft to reduce the client server network traffic and CPU time usage during large data transfer.

Very nice idea. Details here: http://msdn.microsoft.com/en-us/library/windows/desktop/hh848056(v=vs.85).aspx

However, if you have Hyper-V+VHDX files, even with a supposed hotfix, when you use the Live Storage Migration feature of the cluster, you will have a dead, corrupt VHDX file in the end. And if like me you had a bunch of databases in it, your day won’t start well.

Here’s how to disable ODX until a real fix is available:

  1. Open a Windows PowerShell session as an administrator.
  2. Check whether ODX is currently enabled (it is by default) by verifying that the FilterSupportedFeaturesMode value in the registry equals 0. To do so, type the following command:
    Get-ItemProperty hklm:systemcurrentcontrolsetcontrolfilesystem -Name "FilterSupportedFeaturesMode"

     

  3. Disable ODX support. To do so, type the following command:
    Set-ItemProperty hklm:systemcurrentcontrolsetcontrolfilesystem -Name "FilterSupportedFeaturesMode" -Value 1