Currently I have a system with physical machines. On one machine I have a stand alone ArcGIS Desktop Basic license along with a stand alone Network Analyst Extension. This is my 'primary' deployment; A computer assisted dispatch (the other CAD) package makes calls to this machine for geocoding addresses and then routing responses to the returned geocoded point.
Another physical machine is a license server for a concurrent ArcGIS Desktop Standard license along with a concurrent Network Analyst Extension. On any given day, I utilize the concurrent licenses for my day to day GIS work. However, if the primary machine described above goes south or is taken down for maintenance, this second physical machine takes over as the geocoder and network analyst response. Obviously I don't do any day to day work until the situation improves and the primary machine is back up as my concurrent licenses are tied up dispatching calls.
The plan is to go virtual all the way around, so that the only physical machine will be the one on my desk and the primary and secondary deployments will be virtual. If you are still with me:
Does/Can my licensing change with the new scenario?
How is a license server deployed in a virtual environment?
Clearly I'm a GIS guy with just a partial grasp on the virtual world....