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April 7th, 2026 06:15
I/O Warning (Yellow indicator flashing)
Hello!
I have a DELL FX2s chassis, and the yellow I/O indicator on the front panel has lit up.
The status of the nodes and the chassis itself is “OK.”
I periodically see the following event in the logs:
HWC8503: The internal communication between the Chassis Management Controller (CMC) and the ~~1~ control panel is restored.
The CMC controller firmware version is 2.40.
The FN410T modules have also been checked; they are fine.
Please advise what might be causing the I/O indicator to light up?
I thought about rebooting the CMC controller, but I’m concerned that this might affect the nodes’ operation.
Thank you.
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DELL-Joey C
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April 10th, 2026 05:27
Hi,
Rebooting the CMC will not affect the nodes.
Here are some of the recommendation:
Reboot the CMC: Proceed with a soft reboot of the CMC to clear the communication hang-up and reset the sensor states. You can do this from the CMC Web interface by navigating to Chassis Overview > Troubleshooting > Reset Components > Reset CMC .
Update CMC Firmware: You are currently running CMC firmware version 2.40, which is an older release. Dell frequently releases firmware updates that resolve intermittent I2C communication drops and false-positive sensor alerts. Updating the CMC firmware is highly recommended and, just like a standard reboot, is completely non-disruptive to your running compute nodes.
Physical Reseat (if necessary): If the soft reboot or firmware update does not clear the yellow indicator and the HWC8503 logs persist, the connection might be physically loose. You can try physically reseating the CMC module by pulling it out of the back of the chassis and sliding it back in. If the issue remains, the internal cable connecting the front control panel to the midplane or the control panel board itself may be failing and require replacement.