I am in the process of moving an Enterprise Portal with a hosted ArcGIS and DataStore from a Win2008 physical server to a Win2012 virtual server. I also plan to upgrade from the 10.3.0 suite to the 10.3.1 suite, but was advised to get the machine move done first. I plan to do a backup/restore on the DataStore, and to move over the data directories from both the arcgisserver and the arcgisportal. Does anybody know of potential problems with this approach?