An oil pan provided with a drain mechanism in which an adjustable valve body is disposed in a drain opening in the oil pan wall and is adjustable between a closed position and an open position. The housing 30 is interposed between the base 24 and the magnet 25, and the plan-view shape of the base 24 has a portion which elongates more outwardly than the width center of the magnet 25. Using a prescribed protocol, the server apparatus acquires the device-related log information and transmits this information to the client apparatus by inter-process communication.