[CentOS] UPS question

Tue Sep 30 18:41:46 UTC 2014
Digimer <lists at alteeve.ca>

On 30/09/14 02:33 PM, John R Pierce wrote:
> so I have a bunch of servers at work that are on DUAL UPS's (1 per each
> of 2 power supplies).   Its mostly HP gear, but also some Sun and IBM.
> Ideally I'd like the system to not go into shutdown unless BOTH UPS's
> that a particular box is plugged into (there's actually 4 UPS, 2 per
> each of 2 racks).    Has anyone ever configured anything like that with
> NUT or whatever?
> Right now, I'm running without any UPS monitoring software, as the whole
> building is on a generator that comes on 60 seconds after a power
> failure, so my 7kVA(!) UPS's don't see much use, and also I just
> installled these new racks and UPS's and haven't really had the time to
> sit down and figure it all out.

I do this with APC UPSes and apcupsd. I find it well worth the effort as 
I have a (separate) program that checks the UPS state every 30 seconds 
and emails me if there is a notable state change. This has caught 
multiple power issues coming from the mains.

I show how I do this as a sub-section in a larger tutorial, if you are 


I had to make some changes to the apcupsd init.d script to read/use 
multiple UPS config files. I also disabled the automatic power off 
features as, by default, it would have triggered a shutdown as soon as 
one UPS dropped. This is useless if the other UPS is fine, of course. 
That separate scanner program handles the smarts for deciding when to 
shut down based on the strongest of the available UPSes... but that's 
not really covered here.


Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without 
access to education?