How do I change the database file location for couchdb?

That is in local.ini

[couchdb]
database_dir = /path/to/the/databases
view_index_dir = /path/to/the/views

Good luck!

You could also take advantage of symbolic linking. Move the contents of /var/lib/couchdb into your desired directory, and create a symbolic link. Be sure to give the couchdb user permissions to the symlink.