Dell Networking: Basic Fan Troubleshooting for Switches with Removable Fan Units

Dell Networking | Basic Fan Troubleshooting for Switches with Removable Fan Units:

1. Look for visual and auditory evidence of fan operation:

Visual:

1. All installed fans should be visibly spinning.
2. The switch itself has one or more model-specific LEDs. Possible locations include:
   1. FAN LED Indicator:  An illuminated four-bladed fan-shaped icon or LED marked with a fan-shaped icon at the front of the unit
      • Depending on the model, a solid green or unlit LED can indicate normal operation.
      • Most units indicate a fan fault or failure with a flashing yellow LED. 
         
   2. System LED Indicator:  An illuminated electrocardiogram-shaped icon or LED marked with an electrocardiogram-shaped icon at the front of the unit
      • A blinking yellow System LED indicates a noncritical system error, which may include a single fan unit failure.
      • A solid yellow (amber) System LED indicates a critical system error, which may also result from multiple fan unit failures.
         

   3. Fan Unit LED Indicator:  An LED on the rear of the switchbox, often on the fan unit itself

       

Auditory:

1. Excessively loud fan operation or no sound at all may be indicative of a fan issue.

2. Verify the operational status of the fan through the Command-Line Interface (CLI), including fan direction and speed, using the appropriate command for the platform:
   1. OS6:

console> show system fan
Fans:
Unit  Description  Status
----  -----------  ------
1     Fan 1        OK
1     Fan 2        OK
1     Fan 3        OK    

2. OS9: 

DellEMC# show system

Stack MAC                  : 34:17:eb:f2:xx:xx
Reload Type                : normal-reload [Next boot : normal-reload]

-- Unit 1 --
Unit Type                  : Management Unit
Status                     : online
Next Boot                  : online
Required Type              : S4048-ON - 54-port TE/FG (SK-ON)
Current Type               : S4048-ON - 54-port TE/FG (SK-ON)
Master priority            : 14
Hardware Rev               : 2.0
Num Ports                  : 72
Up Time                    : 33 min, 51 sec
Dell Networking OS Version : 1-0 (0-5005)
Jumbo Capable              : yes
POE capable                : no
FIPS Mode                  : disabled
Burned In MAC              : 34:17:eb:f2:94:c4
No Of MACs                 : 3

--  Power Supplies  --
Unit   Bay   Status       Type    FanStatus   FanSpeed(rpm)
---------------------------------------------------------------------------
  1     1    up           UNKNOWN up          10704
  1     2    absent               up          0

--  Fan  Status  --
Unit Bay   TrayStatus  Fan1    Speed   Fan2    Speed
------------------------------------------------------------------------------------
1    1     up          up      10134   up      10031
1    2     up          up      10031   up      10031
1    3     up          up      10031   up      10031

Speed in RPM

3. OS10: 

S4148U-1# show system brief

Node Id           : 1
MAC               : e4:f0:04:c3:xx:xx

-- Unit --
Unit  Status      ReqType     CurType     Version
----------------------------------------------------------------
1     up          S4148U      S4148U      10.5.5.6

-- Power Supplies --
PSU-ID  Status      Type    AirFlow   Fan  Speed(rpm)  Status
----------------------------------------------------------------
1       up          AC      NORMAL    1    13344       up

2       fail

-- Fan Status --
FanTray  Status      AirFlow   Fan  Speed(rpm)  Status
----------------------------------------------------------------
1        up          NORMAL    1    9590        up
                               2    9614        up

2        up          NORMAL    1    9590        up
                               2    9614        up

3        up          NORMAL    1    9614        up
                               2    9590        up

4        up          NORMAL    1    9590        up
                               2    9590        up

4. SONiC: 

E3248PXE-ON-U35# show platform fanstatus
-----------------------------------------------------------------------
Fan            Status         Speed (RPM)         Direction
-----------------------------------------------------------------------
FAN 1          OK             5698               exhaust
FAN 2          OK             5657               exhaust
FAN 3          OK             5674               exhaust

3. Remove the affected fan unit from its slot on the back of the switch.
4. Visually inspect the fan unit for damage (dents, burn marks, and similar signs of observable defect).
5. Swap the suspected fan unit with another working fan.
   1. If the issue is now present on the new slot after swapping, the fault is with the fan unit.
   2. If the issue remains on the original slot after swapping, the fault is with the fan unit slot.
   3. If both fan units present normal operation following the swap, update OS and firmware to apply known firmware-related fixes.

6. Create and submit a Work Order to replace the faulty component identified in Step 5.