Here is how you can enable MPIO quickly in a Windows server 2012 core installation like Hyper-V 2012 (without GUI).
Run this command to install MPIO feature:
ocsetup MultipathIo /norestart
You will have to restart the computer later on. MPIO won’t work until the server is restarted.
After the reboot you can either use the command mpclaim to enable MPIO for unclaimed devices [meaning those LUNs which appear like 4 separate disk drives but are actually one LUN connected via 4 paths]:
mpclaim –r –i –a
Note: I am getting an error saying that an invalid switch was specified. However I ran this command BEFORE rebooting the Hyper-V server. YMMV.
or you can use the MPIO GUI to do the same. Start the GUI using this command:
Hint: Go to the discover multipaths tab and click on “add”