[Nut-upsuser] false alerts/shutdown

[Stijn Gruwier]

Hello,
At first, thanks for you advice and clarification on the MAXAGE and 
DEADTIME configuration values.

>> I've installed Nut (2.0.5) on RedHat a week ago, and upsmon seems to
>> generate false alarms every hour:
>>
>> ...
>> Jun  8 06:10:56 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on line power
>> Jun  8 06:35:46 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on battery
>> Jun  8 06:35:51 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on line power
>> Jun  8 07:24:47 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on battery
>> Jun  8 07:24:52 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on line power
>> Jun  8 08:27:07 nutevalserver upsmon[2849]: UPS
>> usb-mge-evolution at localhost on battery
>> ...
>>     
>
> What makes you think these are false alarms?
>   

I have 2 reasons for believing these are false alarms:

1) The UPS doesn't beep and none of the status leds change when this 
occurs. I configured nut to page me for 'on battery' events, and while 
working in the server room I witnessed how NUT complained but the UPS 
didn't give a sign. In contrast, when it goes on battery because I pull 
the plug, it beeps, leds flash, ...

2) Three other servers (not backed up by ups) who share the same power 
distribution unit as the UPS are not affected. If these alarms are real, 
it means voltage drops to 160V. I thought that would shut a server 
down.  Maybe you are right and a server can handle this for a few seconds?

>> When I went to the server room almost immediately,
>> the UPS was fully charged, but the server had shut down.
>>     
>
> How did you determine the battery was fully charged? Did you execute a
> battery capacity test at that time? Or did the UPS indicate that the
> battery was full? 
>   
I didn't do a battery test, just looked at the status leds.

> It may also mean that the mains to your UPS is browned out (bad cables,
> bad socket) or that it just senses that it is, while it actually isn't
> (trips on every mains glitch). For testing purposes, I keep one unit that
> does the latter. When the distribution transformer around the corner steps
> to another tap, it will always go to battery for couple of seconds. This
> usually happens a couple of times around six in the morning and around
> nine in the evening, every working day.
>   
I'm almost sure the mains are OK since the building is less than 2 years 
old. Also I connected the UPS to another socket across the room to no 
avail. I agree there might be electrical glitches, but wouldn't the UPS 
beep then?

Regards,

Stijn Gruwier

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