This FAQ page used to be sticky, but , in their wisdom, WD decided not to make it sticky again after a recent forum replacement.
It contains what i’d suggest is the definitive guide to disabling the wdmcserverd etc functions:
/etc/init.d/wdmcserverd stop
/etc/init.d/wdphotodbmergerd stop
# to keep it from restarting after a reboot
update-rc.d wdphotodbmergerd disable
update-rc.d wdmcserverd disable