[Nut-upsuser] UPS reboots with APC UPS

stefanos at karandreas.gr stefanos at karandreas.gr
Thu Sep 3 20:10:11 BST 2020

> On 2020-09-03 18:29, Roger Price wrote:
> NUT is designed to
>  1. Power off the system attached to the UPS when some criteria is
> reached, eg. status [LB]
>  2. Some time later, in your case ups.delay.shutdown = 20 seconds, the
> UPS shuts down its power outlets.
I see, I wasn't aware of that part.
While that holds true for the 1st example-case I stated on the 2nd one 
it was certainly couple of minutes before the ups did it's click sound 
(thought it was reboot but as you corrected me it's cutting power to the 
plugs). That could have been a fluke though?
>  3. When wall power returns, the UPS turns on it's power outlets and
> this provokes the attached system to power up.
> In your case, instead of powering off the attached system, you begin a
> suspend/hibernate, but continue to take power from the UPS.  But the
> ups.delay.shutdown will still have an effect, and the UPS will turn
> off it's outlets.
> I don't see clearly how you intend to operate, but you may need to
> neutralize the "delayed shutdown" order to the UPS.  However if you do
> this, I don't see how it will be possible to resume from suspend.
M2 is usually suspended when I am not physically there. Power cuts out. 
After x minutes LB is reached and M1 is set to suspend while power is 
not cut of the plugs of the UPS unit at any point in time. UPS operates 
with minimal load on it (basically two monitors from M2 that are on 
standby). Power comes back, everything continues to be as is. The resume 
from suspend will be manual (i.e. click the power button). I am fine 
with this approach and should work just fine right?
There is also wake-on-lan that works on suspend but would require a 
raspberry-pi or something similar.
> I suspect that you would be best served by a big UPS which will carry
> you through most power outages, and use NUT to shutdown (not suspend)
> on LB, when it's clear that wall power has gone for the day.  There is
> no automatic suspend in that scenario.
As I think more of it, with the information you provided, the NUT 
approach is better as it allows for unattended restart of the machines 
regardless of downtime (well unless it exceeds the battery life). 
Regrettably the fact that M2 is suspended when I don't use it, is 
incompatible with that approach and not using suspend on M2 would mean 
starting up everything on M2 at least once per day.

Do you know whether ups.delay.shutdown -1 or ups.timer.reboot -1 
neutralize it? Or I will have to trial & error?

Thank you for your help!
> Roger

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