Description

There is a PSM Input Under Voltage Failure alarm generated when the PSM goes offline due to low voltage.
After it is recovered, this alarm remains.

Symptoms

The switch generates chassis alarm that PSM 0 Input Under Voltage Failure: 
root@QFX5220> show chassis alarms
Alarm time               Class  Description
2023-01-01 00:00:00 PST  Major  PSM 0 Input Under Voltage Failure <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

The switch reports that the PSU status as OK. 
root@QFX5220> show chassis environment
Class Item                           Status     Measurement
Power PSM 0                          OK         30 degrees C / 86 degrees F <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Temp  FPC 0 Sensor TopMiddle         OK         28 degrees C / 82 degrees F
      FPC 0 Sensor TopFrontLeft      OK         25 degrees C / 77 degrees F
      FPC 0 Sensor TopBack           OK         30 degrees C / 86 degrees F
      FPC 0 Sensor BottomBack        OK         29 degrees C / 84 degrees F
      FPC 0 Sensor CPUTopLeft        OK         28 degrees C / 82 degrees F
      FPC 0 Sensor CPUBottomMiddle   OK         31 degrees C / 87 degrees F
      FPC 0 Sensor CPUTopBackRight   OK         28 degrees C / 82 degrees F
      FPC 0 Sensor TH3 Max Reading   OK         43 degrees C / 109 degrees F
      Routing Engine 0 CPU Temperature OK       42 degrees C / 107 degrees F
Fan   Fan Tray 0 Fan 1               OK         14400 RPM
      Fan Tray 0 Fan 2               OK         13400 RPM
      Fan Tray 1 Fan 1               OK         14900 RPM
      Fan Tray 1 Fan 2               OK         13700 RPM
      Fan Tray 2 Fan 1               OK         14500 RPM
      Fan Tray 2 Fan 2               OK         13500 RPM
      Fan Tray 3 Fan 1               OK         14700 RPM
      Fan Tray 3 Fan 2               OK         13400 RPM
      Fan Tray 4 Fan 1               OK         15000 RPM
      Fan Tray 4 Fan 2               OK         13500 RPM
      Fan Tray 5 Fan 1               OK         14500 RPM
      Fan Tray 5 Fan 2               OK         13500 RPM

root@QFX5220> show chassis power
Chassis Power        Voltage(V)    Power(W)

Total Input Power                    260
  PSM 0
    State: Online <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    Input 1             213          260
    Output            11.97        235.71
    Capacity           1600 W (maximum 1600 W)
  PSM 1
    State: Offline
    Output

System:
  Zone 0:
      Capacity:          1600 W (maximum 1600 W)
      Allocated power:   1241 W (359 W remaining)
      Actual usage:      259 W
  Total system capacity: 1600 W (maximum 1600 W)
  Total remaining power: 359 W

Solution

Once this alarm is displayed, it remains even if it is recovered.
Restart the affected device or remove/re-insert a power supply during a maintenance window, then monitor for any errors.
Contact your technical support representative if the issue persists after this operation.

Modification History

2023-06-23 : First Version
2023-09-28 : Making it public for customer visibility and better reach