Fan Speed Warning - Troubleshooting Guide

Fan Speed Warning - Troubleshooting Guide

Purpose

Provide guidance for engineers to investigate and respond to Fan Speed Warning alerts generated by the monitoring system.

This KB article ensures that engineers follow a consistent troubleshooting procedure when cooling-related alerts occur.


When to Use

Use this KB when the monitoring system triggers the alert:

Fan Speed Warning

This alert indicates that fan speed has dropped to 2000 RPM or below, which may indicate a cooling issue.


What the Alert Is

The Fan Speed Warning alert occurs when the system detects that a server fan is running at or below the threshold value.

Condition

Fan Speed ≤ 2000 RPM

This may indicate:

  • Fan degradation

  • Dust accumulation

  • Airflow obstruction

  • Early stage fan failure


Summary

Failing or underperforming fans directly impact system cooling.

If not addressed, this may lead to:

  • Increased system temperature

  • CPU or GPU thermal throttling

  • Thermal shutdown of the node

Early detection allows preventive maintenance before the issue becomes critical.


Severity

P4 – Low Impact

This is a warning alert and does not immediately impact system operation, but it should be monitored and investigated.


L1 Engineer Actions

Follow these steps when the alert is received.

Step 1 – Log Alert Details

Record the alert information from the monitoring system.

Capture:

  • Node hostname

  • Alert timestamp

  • Fan speed reading

  • Alert severity

Step 2 – Monitor Alert Behavior

Check if the alert is persistent or transient.

If the fan speed returns to normal, continue monitoring.

Step 3 – Escalate if Alert Persists

If the alert continues:

  • Inform the L2 engineer

  • Create an internal support ticket

Step 4 – Update Issues Tracking

After confirmation with L2:

  • Add the incident to the Issues Master Sheet for tracking and reporting.


L2 Engineer Actions

Step 1 – Verify via BMC

Access the BMC / IPMI interface and verify fan sensor readings.

Check:

  • Fan RPM values

  • Fan health status

  • Hardware logs

Example command:

Note: if we need to run "ipmitool" command check server connectivity from the source machine and ipmi executable file or ipmi package must be installed in the same source machine. 
ipmitool sdr type fan

Step 2 – Identify Failed Fan

Determine which fan module has failed.

Check:

  • Fan ID

  • RPM readings

  • Sensor status

Step 3 – Plan Preventive Maintenance

If the fan continues to run below optimal speed:

  • Schedule preventive maintenance

  • Clean the server or replace the fan module if needed

Step 4 – Check for Dust or Airflow Blockage

Inspect the physical server if required.

Verify:

  • Dust accumulation

  • Blocked air vents

  • Proper airflow inside the rack

Step 5 – Try Physical Reseating the Fan

If the server supports hot-swappable fans:

  1. Remove the faulty fan module

  2. Reinsert the fan properly

  3. Verify the fan is detected again

Step 6 – Replace Faulty Fan

If reseating does not resolve the issue, replace the fan module.

Step 7 – Escalate to OEM

If the issue persists:

  • Collect hardware logs

  • Record node serial number

  • Capture sensor output

Open a support case with the OEM vendor.

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