You can configure most aspects of your Berkeley DB environment by
                using the DB_CONFIG file. This file must be
                placed in your environment directory. When using the BDB SQL interface, this is
                the directory created alongside of your database. It has
                the same name as your database, followed by a
                -journal extension. For example, if your
                database is named mydb.db, then your
                environment directory is created next to the
                mydb.db file, and it
                is called mydb.db-journal.
            
                If a DB_CONFIG file exists in your
                environment directory, it will be read for lines of the
                format NAME VALUE when
                your environment is opened. This happens when your
                application starts up and creates its first connection to
                the database.
            
One or more whitespace characters are used to delimit the two parts of the line, and trailing whitespace characters are discarded. All empty lines or lines whose first character is a whitespace or hash (#) character are ignored. Each line must specify both the NAME and the VALUE of the pair. The specific NAME VALUE pairs you can use with the BDB SQL interface are documented in the Berkeley DB C API .
In some cases, you must either specify a configuration option before the environment is created, or the environment must be re-created before the configuration option will take effect. The documentation for each configuration option will indicate where this is true.
                    In order to provide the DB_CONFIG file before
                    the environment is first created, physically make the
                    environment directory in the correct location in your
                    filesystem (this is wherever you want to place your
                    database file), and put the DB_CONFIG
                    file there before you create your database.
                
                    Some DB_CONFIG parameters require you to
                    re-create your environment before they take effect.
                    The DB_CONFIG parameter descriptions
                    indicates where this is the case.
                
To re-create your environment:
                            Make sure the DB_CONFIG file
                            contains the following line:
                        
add_data_dir ..
                            (This line should already be in the
                            DB_CONFIG file.)
                        
                            Run the db_recover command line utility. If
                            you run it from within your environment
                            (-journal) directory, no
                            command line arguments are required. If you run
                            it from outside your environment directory, use
                            the -h parameter to identify
                            the location of the environment:
                        
db_recover -h /some/path/to/mydb.db-journal