This is a quick post for simple error that you might see in Cisco UCSM.
Affected object: sys/chassis-2/fan-module-1-2
Description: Fan module 1-2 in chassis 2 temperature: upper-critical
This may indicate that there is hardware problem with the fan and it needs to be replaced but quite often it indicates logical problem. There are a few bugs depending on the version that UCS is running that might cause this behaviour.
As we can see from the error the problem is with the fan in chassis 2.
If you click on the blue text it will open a new window and you’ll be able to see which fan it is.
The first thing you can try is to reseat the fan and see if the error goes away. If it does not then it most likely hardware issue.
In this case the error has cleared.
This error might reappear in couple day/weeks or months or it could happen on the other fan. There is a known I2C bug in UCS. To clear i2c bus it is advised to reseat all fans, PSUs and IOmodules(one at a time).
The bug was fixed in late 1.4(3*) version but was reintroduced again in 2.0 version. It should be fixed in latest version.
I UCS system affected by this bug than you still need to reseat components as the upgrade alone will not clear the I2C bus.
IMO it would be best to reseat them before upgrading as at least you’ll be upgrading a healthy system.