Posted on December 20, 2019 8:38 pm
 |  Asked by Chandra
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Hello Team,

I was in mid of testing for customer environment & while doing some platform checks & I found Both power-supplies showing speed stability under command “show environment cooling” as “FW Override”

I am quite surprise as in configs I haven’t configured any override options with any value for environment. I tried to physical reset the power-supply but again I got the same “FW Override” while in other boxes it shows “stable”

Below is output for reference & would appreciate your help.

show environment cooling
System cooling status is: Ok
Ambient temperature: 23C
Airflow: port-side intake
Config Actual Speed Stable
Fan Status Speed Speed Uptime Stability Uptime
————– —— —— —— ——- ———– ——-
1/1 Ok 30% 31% 1:06:59 Stable 1:06:41
2/1 Ok 30% 31% 1:06:59 Stable 1:06:41
3/1 Ok 30% 31% 1:06:59 Stable 1:06:41
4/1 Ok 30% 30% 1:06:59 Stable 1:06:39
PowerSupply1/1 Ok 30% 34% 1:06:37 FW Override N/A
PowerSupply2/1 Ok 30% 33% 1:06:38 FW Override N/A

Answered on December 20, 2019 8:40 pm

Hello Chandra,

Thank you for writing to the forum.

Basically there are two mechanisms that can set the power supply fan speed, one is software (EOS) and another is the power supply's internal firmware. The way the power supply firmware works is that it takes the greater of these two values and uses that for the fan speed. So for example, if the power supply's firmware decides the fan speed to spin at 40% to cool the power supply based on its sensors, but EOS wants the fan to spin at 60%, the fan will actually spin at 60%. Likewise, if the firmware decides the fan should spin at 60%, but EOS tries to drive the fan to 40%, the fan will still spin at 60%. The latter case (where the firmware setting takes precedence) can result in strange output in "show env cooling" because it will say the configured speed is 40% while the actual speed maybe 60%.
Hence we added the output in "show env cooling" to say "FW Override" when the firmware setting takes precedence over EOS's setting and is not indicative of an issue.


Thanks Dharmesh, So are you saying that this is normal/default behaviour & "show env cooling" output "FW Override" is nothing related to any abnormal issues to power-supplies ?
(Chandra at December 20, 2019 9:24 pm)

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