Cisco Nexus 9K Fan issue

[yadhukrishna]

I have a cisco 9k Nexus switch which is having a FAN issue(Burgundy color), 

CISCO NXA-FAN-30CFM-B this model should actually work as a port intake but when i checked in CLI it shows as back to front. Is there a troubleshooting I can do? Or do I need an RMA?

 

 

[Kasun Bandara]

hi @yadhukrishna can you share the '#show inventory' output and hardware components outputs. hide the serials. mentioned part code is port side intake. if you see different part code, thats the ordered part when ordering from cisco. 

if there is mistake from cisco side, you can contact your cisco partner or cisco AM to clear. 

[yadhukrishna]

Hi,

Thanks for the response

I hope this helps.!!

Fan1(sys_fan1) NXA-FAN-30CFM-B -- back-to-front Ok
Fan2(sys_fan2) NXA-FAN-30CFM-B -- back-to-front Ok
Fan3(sys_fan3) NXA-FAN-30CFM-B -- back-to-front Ok
Fan4(sys_fan4) NXA-FAN-30CFM-B -- back-to-front Ok
Fan_in_PS1 -- -- front-to-back Ok
Fan_in_PS2 -- -- front-to-back Ok

[pieterh]

does the PSU color match the fan clolor ?

[yadhukrishna]

Both(Fan & PSU) are in Burgundy color. I checked on another cisco 9k which we have here, its also having the same parts, but working as expected(Front to back)

[yadhukrishna]

@Kasun Bandara @pieterh  any suggestions?

[Kasun Bandara]

seems like a representation issue in OS. if you have any way to confirm physically, check if the fan works as intended which should be. try  recommended OS version for device to see if there is any OS related issue.

meanwhile you can open TAC if this is considerable fault item.

[pieterh]

this sounds odd, but it could be the fan or the psu is faulty or is painted the wrong color

the partnumber of the PSU is not visible is your snippet from "show inventory"
do a show inventory again and retreive the PSU partnumber

as an extra diagnostic step you can swap a fan and/or PSU with the switch that behaves as expected

[Paul Chapman]

It's possible that this is a cosmetic bug. Here is show output from two switches in my lab. The N5K shows "front-to-back" while the N9K shows "back-to-front". Both switches are port-side exhaust.

Lab-5548-A# show env fan detail 
Fan:
---------------------------------------------------
Module  Fan  Airflow        Speed(%)  Speed(RPM)  
             Direction                             
---------------------------------------------------
1       1    Front-to-Back  60        15517       
1       2    Front-to-Back  60        11203       
1       3    Front-to-Back  60        15340       
1       4    Front-to-Back  60        11203       
2       1    Front-to-Back  60        16023       
2       2    Front-to-Back  60        12026       
2       3    Front-to-Back  60        16167       
2       4    Front-to-Back  60        11842       

===================================================

ONT-INFRA-CORE1# show environment fan 
Fan:
---------------------------------------------------------------------------
Fan             Model                Hw     Direction       Status
---------------------------------------------------------------------------
Fan1(sys_fan1)  NXA-FAN-30CFM-F      --     back-to-front   Ok 
Fan2(sys_fan2)  NXA-FAN-30CFM-F      --     back-to-front   Ok 
Fan3(sys_fan3)  NXA-FAN-30CFM-F      --     back-to-front   Ok 
Fan4(sys_fan4)  NXA-FAN-30CFM-F      --     back-to-front   Ok 
Fan_in_PS1      --                   --     back-to-front   Ok
Fan_in_PS2      --                   --     back-to-front   Ok
Fan Zone Speed: Zone 1: 0x80
Fan Air Filter : NotSupported

Use a strip of paper to check airflow direction on each fan and PS. If they are all going the same direction, then you will have no issue.
Last item to note: Reversing air-flow direction via hot-swap is not technically supported. You must power cycle the switch when you perform this task. And yes, I did open a TAC case to find this out.

HTH

-PSC

[pieterh]

>>> but when i checked in CLI it shows as back to front <<<    this is not contradictory to "Port-side Intake"!
picture this:
- you mount the switch as top-of-rack in a rack together with rack-model servers (1U, 2U etc)
- you keep the network-ports at the same-side as those rack-servers have which is at the rear, not the front
  (this keeps UTP patching easy, no need to pass cabling from the back to the front or visa versa)
then port-side intake comes down to "back-to-front" airflow 
as most servers have front to back airflow this reverse flow is undesirable

and you need either
- mount the switch the other way around (with ports at the other side from the server network ports)
  which results to longer cables from the front to the back of the cabinet
- or reverse the airflow to  Port-side Exhaust which is then same as front-to back