It's true that doing a vmotion will use some resources and possibly throw alarms depending on what all is going on at the time... if you know that you were doing something that would probably influence resource usage, expect a few alarms along the way (depending on the size of your VM clusters and datacenters of course).
Alarms in Virtual Center will go away after they have passed out of the window of time that Virtual Center worries about them. When I first saw an alarm in Virtual Center, I freaked out until I realized that it was an alarm from a while ago and the VM in particular was fine and working normally. Alarms happen and I've learned to look at them without going into a panic since the threshold by default is pretty long. Once the window of time passes, so will the alarm state.
