In MDSM you can change the current controller (owner), but also change the preferred path. Just right click the virtual disk and under change you change the current owner, which also changes the preferred owner. Only when a disk is on a non-preferred controller does it let you change controller without changing the preferred (you can then chose to just change the preference or change the disk to the other controller).
  Hi All   I went through the procedure Friday to change the battery pack on raid controller 0, however now all my diskgroups are only using raid controller 1 and they all marked it as "Prefered path". I can of course force them to use raid0, however this will cause the box to show error "Need attention" as some VD are not on preferred path.   Anybody now hw do i change the preferred path setting , so i can balance the load ?   Environment: vSphere 5, MD3200i dual controller.  
All VD on same preferred path MD3200i after batterypack replacement !