Hello Kurt,
For the X440 platforms we have 3 temperature sensors:
- ambient for fan control
- ambient for EXOS temperature reporting
- hot-spot for EXOS debugging
EXOS cannot read or display the value of the fan control temperature sensor (1). The temperature reported by EXOS is separate from the fan controller, therefore the temperature reported by EXOS may not align to the fan off/on, low speed/high speed behavior.
Fan Status includes Fail and Ok for the set of fans. Fan status can be reported with “show fan". Fan speed cannot be checked as the X440 has no fan controller component.
The data that is displayed within “show temperature” is from
sensor 2:
(debug) X440-24p.3 # show temperature
Field Replaceable Units Temp (C) Status Min Normal Max
---------------------------------------------------------------------------
Switch : X440-24p 28.00 Normal -10 0-48 55
With EXOS debug-mode enabled, we can view the data from both
sensors 2 and 3:
(debug) X440-24p.4 # !cat /proc/extr/temp
Number of temperature sensors=2
Sensor 0) Module=Motherboard(2), type=default(1),
28.00 # sensor 0 is 2 in the above list
Sensor 1) Module=Motherboard(2), type=Hotspot(3),
41.50 # sensor 1 is 3 in the above list
What is the HOTSPOT temperature?
- Apart from default switch temperature sensor, switch will have additional sensor internally and it seems like that internal sensor has reached maximum temperature under normal working conditions. The switch has got a hotspot temperature and it placed internally near to the units which exhibits high temperature reading. By reading the hotspot temperature, the fan will start running and report has 11000RPM.
Note:- We would require debug-mode access to collect the above mentioned outputs.
For the X440-24p (it’s not the same for all X440 models) if the fan control temperature sensor is below 30C the fan speed should be 5900 RPM (half-speed). If the fan control temperature sensor is above 30C the fan speed should be 11000 RPM (full-speed).
Please find below the fan working behavior on Summit X440-48P/T port switches:
- The X440-48P/T port switch fans operate at either high-speed (above ~30C) or low-speed (below ~30C). The fan speed is entirely controlled by hardware.
- The fan speed (i.e. RPM) is not reported to software, nor does the hardware provide any indication to software in what mode (high- or low-speed) the fans are operating.
- The only fan status indication hardware provides to software is a FAN-FAIL signal. This informs software that the fan(s) are either not spinning at all, or they are spinning at a very low (failing) speed.
- Therefore, the only thing software knows about the fans is whether they have failed or not. So in consideration of this, software only reports that the fans are on (running full-speed/not failed) or off (failed).
- We have confirmed this in our internal lab testing with X440-48P/T port switch running in hot chamber. We could see that the software reports fans operational with speed 11000RPM at temperature below and above 30c. It is a product design limitation.
The Summit X440-24t devices have different fan working behavior.
In your scenario,I suspect the HotSpot Temperature can be above ~30C. So, the fans are running in 11000 RPM (high speed). We could collect the outputs from these switches to verify the status.
If you need more information, please do not hesitate to contact us or open a GTAC case.
Regards,
Ram