[Nut-upsuser] MGE Evolution and programmable outlets configuration

Marco Chiappero marco at absence.it
Sat Dec 6 14:34:08 UTC 2008

I'm a MGE Evolution 650 owner and, after putting in place a basic 
configuration for controlling my UPS, I'm going to tune a little bit 
better NUT for my needs.
First of all let me describe my little (SOHO) scenario: I have the ISP 
modem/switch (providing VoIP too, so it's important to keep it running 
as much as possible), a small low power home server and a much hungrier 
PC. The UPS is connected to the server, witch is always up and running.
Basicly the idea is to use the powershare feature for satisfying 
different priorities and a specific powerdown order. When power outage 
occurs I'd like to bring down my PC (connected to outlet2) after a short 
period of time while keeping the server (connected to outlet1) running 
for some more time, maybe untill batteries are around the 30-40% 
capacity, hence leaving some charge for running the phone till batteries 
are (almost) dead.
I have read powersaving.txt but such scenario is not covered in detail 
and I'm not that sure about nut configuration.
First of all I think I have to use upssched for shutting down the 
computers, both connected to the programmable outlets, haven't I? But 
how does the driver communicate to the computers that outlet.X is 
cutting the power since is reaching the 
outlet.X.autoswitch.charge.low/outlet.X.delay.shutdown condition? Does 
it cut the power without any notice? And how the computers get aware 
from witch outlet they are drawing power? Without these information it 
sounds that programmable outlets are almost unuseful and just marketing. 
I mean, if I have to set up a counter in my computers for starting the 
halt sequence it does not make any difference the outlet it is connected to.
Then, since I *do* not want the server to shutdown the UPS, should I run 
upsmon as slave on both the PC and the server?
Please help me to understand a little bit better how to set up NUT, 
thank you.


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