How to reduce FANs RPM on Cumulus Linux (Switch SN2410)?

Hi there, hope you guys are doing great!

I’m using a Cumulus Linux in a SN2410 Switch, and I am wondering how can I reduce/decrease all fans RPM?
Is there any command or configuration file where I can set the fan speed in RPM? I’ve noticed that all of them are running in the maximum speed by default, which makes a loud noise.

Is there any example?

Thanks for your attention!

They are probably not even running at full speed, that only happens when it gets very hot. The speed is dynamically adjusted based on the temperature and you cannot change that in any supported way. This is to prevent various components from overheating.

So @attilla , they are running at full speed all time the switch is powered. FANs speed is not being dynamically adjusted. Every time I check the sensors command, it returns the same RPM for all fans (that is the same of the maximum speed or even higher). My lab temperature is controlled and below 23 °C, so its not “hot” in the lab.

cumulus@cumulus:mgmt:/etc/sensors.d$ sensors
Adapter: i2c-1-mux (chan_id 7)
temp1:        +27.0°C  (high = +80.0°C, hyst = +75.0°C)

Adapter: i2c-1-mux (chan_id 2)
fan1:            21802 RPM
fan2:            18050 RPM
fan3:            21802 RPM
fan4:            18292 RPM
fan5:            21459 RPM
fan6:            18292 RPM
fan7:            21802 RPM
fan8:            18541 RPM

I would like to know how can I make an speed divider ( I believe they are all PWM controlled). Are you sure that Isn’t there any configuration that I can write in the file located at /etc/sensors/ ?

I just want to do it because the noise is too loud in the lab and outside it, and it is not being healthy for other employers to work around it.


Hi Phzera,

This is not correct then, because they should automatically adjust and your environment doesn’t seem to hot. Which CL version are you running, because there has been a specific version that had an issue around this.

Obviously there are non supported ways, but that is not recommended. I would first look if the above is applicable to you.

Hi @attilla,
I’m running on CL 4.2.1.

cumulus@cumulus:mgmt:~$ cat /etc/lsb-release 
DISTRIB_ID="Cumulus Linux"
DISTRIB_DESCRIPTION="Cumulus Linux 4.2.1"

I think that is exactly the version that is affected by the issue, so I would suggest you install 4.4 or if possible for you 5.0 (you would have to move to NVUE though).

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OK @attilla , I’ll try to upgrade to CL 4.4.

Thanks for the support.