Cooling fan speeds on new 9300-24P Catalyst switch

[Christopher Rudi]

Just fired up a brand new 9300 24 port switch to configure and after the boot process finishes the three cooling fans on the back seem to be constantly varying their RPM's. They'll speed up then slow down then speed up then slow down... over and over. It's just an annoyance at this point so I didn't want to bother TAC with it but I was just wondering if anyone else has noticed this? If it is what it is then I'm ok with it. There's not much to see with the "show env" commands other than the fans are OK and the temps are OK. Thanks!

Chris

[Reza Sharifi]

This usually only happens during the boot process. As long as the room temperature is not fluctuating, you should not see this behavior. I would open a ticket with TAC and have them take a look.

HTH

[Georg Pauwen]

Hello Chris,

that doesn't sound right. Check if something is obstructing the airflow. Also, the fan modules are hot-swappable - remove and reinsert them one by one (you always need two working ones), when you have removed one, check if there is dust or dirt on them...

Chapter: Installing a Fan Module

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/hardware/install/b_c9300_hig/b_c9300_hig_chapter_0101.html

[Christopher Rudi · Accepted solution]

I'm just going to let this go for now as the internal temps are good and the fans are showing as "Ok". This is my first go-around with a C9300 but I've got over 120 arriving next month so I'll see how those behave. I pulled one modular fan at a time as suggested but I could still here the RPM's oscillate so it could just be how they are. It'd be nice if the CatOS showed RPM's like Nexus does but oh well. Thanks for the responses guys!

[dangustafson]

Did you ever find a solution to your problem?  We just got a bunch of 9300s recently and they are also experiencing the oscillating fan issue.  I checked show env temp and the temperatures are within the green range.

I am located on the California coast, these things sound like the faint howl of the Tsunami warning siren.

THANKS!

[dangustafson]

Problem solved!

Anybody who has this fan oscillation problem needs to check their IOS version.  We experienced this fan oscillation problem on over one hundred 9300 switches running 16.6.3.  A coworker noticed 1 single switch in a cabinet that did not exhibit this problem.  It was running 16.6.2.  So apparently something changed after 16.6.2 that caused this terrible fan oscillation.  Our experience is that you need to update much further, to 16.9.1 in order to avoid the fan oscillation issue.

Brief rundown of our IOS experience with 9300 series switches:

16.6.2 - Quiet fans, but has a terrible bug with Intel NICs using Energy Efficient Ethernet

16.6.3 - Very distracting and annoying fan oscillation

16.6.4 - Very distracting and annoying fan oscillation

16.9.1 - Quiet fans, all of us in our crew agree they seem even quieter than 16.6.2

Honestly, I don't think anybody ever thought this oscillation could be addressed/fixed with firmware.

[hunnymonster]

For anyone wishing to stay in the 16.6.x train - this was fixed in 16.6.4a and remains fixed in 16.6.5 & 16.6.6