Yes, the DB_CONFIG file is a function of Berkeley DB, not Citadel. If that
file is found in the data/ directory, you can use it to "redirect" both the
database files and the log files to other locations. You are correct in
observing
that there is no way to move the configuration of database file locations
into the database.
I suppose it would be possible to build a standalone utility to manipulate
DB_CONFIG while Citadel Server is not running, setting the file locations
and moving the files to the new locations if they exist, and also tuning the
other options that are available in DB_CONFIG. I'm not sure how useful it
would be, considering that anyone smart enough to know how to do that kind
of tuning is probably smart enough to edit the file.