Warning: require(db.php): Failed to open stream: No such file or directory in /volume1/web/index.php on line 2

Fatal error: Uncaught Error: Failed opening required 'db.php' (include_path='.:/usr/share/pear') in /volume1/web/index.php:2
Stack trace:
#0 {main}
  thrown in /volume1/web/index.php on line 2