Everything was running smoothly until the client began seeing four LUNS, disabling the Hyper-V Clustering services. In this case they only had one LUN presented but were seeing the four paths from their HP P2000 Fibre Channel Storage Array in the Microsoft Disk Manager.
MPIO Secret Unveiled
The trick to get the four paths to sew up into one is the MPCLAIM command:
First, ensure MPIO is installed using the GUI or your favorite Powershell command “Enable-WindowsOptionalFeature –Online –FeatureName MultiPathIO”. (A reboot will be required)
Engage MPIO and get a nice, clean LUN combination with the [mpclaim.exe -r -i -a “”] command. For this, you will want to use an elevated command prompt. The -r forces a reboot.
If you don’t want to reboot yet use -n in its place, however keep in mind that a reboot is required for full implementation.
…and Boom! There ya go…
You may get an msvcr100.dll error when issuing the mpclaim command, which can be fixed by installing the Microsoft Visual C++ 2010 SP1 Redistributable Package (x64). It does not, however, prevent MPIO from engaging.
Happy Hyper-V Clustering!