FDB isnt something one would enable or disable on a network device as normal operation. The FDB fowarding database table is used by a Layer 2 device (switch/bridge) to store the MAC addresses that have been learned and which ports that MAC address was learned on.
NNMi uses these tables to build the layer two connectivity between devices by cross referencing the tables at a per-device and per instance (for virtualized switching contexts).
If FDB were disabled on a switch , it would stop working.
Have a nice day :)
Andy Kemp I've lasted longer in the technology industry than most certifications.