You could make the file immutable (premanently fixed) but if the subscriber_ids.csv gets updated by DVSwitch the update will fail as immutable files canot be changed.
Example is my cloud server when updated changed my resolvers (DNS resolvers) to whjat THEY wanted, not what I had set. Making the resolver.conf file immutable protects my changes.
So how to do this: chmod +i subscriber_ids.csv (the letter is a small (eye) )
and if you want to make your own changes you have to remove the immutable flag with: chmod -i subscriber_ids.csv
the examples are if you are in the same directory as the file if you are not, the a fill path to the file is needed -- e.g. chmod +i /etc/resolver.conf
