Preventing a rogue media server after the decommissioning of a media server
Veritas recommends that you perform multiple tasks after you run the nbdecommission command. Veritas has added another recommendation to this list:
Uninstall NetBackup from the media server or remove that media server from the environment. After this configuration change, the media server daemons do not have permissions to communicate with the master server and should no longer be started.
For more information about the decommission recommendations, review the Post decommission recommendations section in the NetBackup Administrator's Guide, Volume I