Today, all (four) pump units along the south arm have failed. I supporsed that the dry-pump replaced yesterday in the south end faild at first, then other pumps also went to stop. The pressure of the arm duct increased to 20mbar. The dry-pump in the south end was broken with "ALM05 MP STEP", The other pump units were recovered. Since the pressure  of the arm duct is too high, the GVs between the pumps and the duct are closed. It is necessary to evacuate the duct with the large RP so as to be lower than 0.1mbar.