@Doomed_Daniel@vees@dan In many situations you don't want to keep the mapping file, because it creates differences between identical hardware based on the history of a particular server. One out of your eight hardware-identical fileservers having a different network name because you had to move it to the spare chassis (or swap its add-on network card) at one point is a special sort of hell.
(Also, not all reinstalls are planned in advance. Sometimes the disk blows up.)