UPS / non-UPS environmental monitoring

Cris Rhea crhea at
Wed May 12 11:46:47 CDT 2004

> Message: 1
> Subject: UPS / non-UPS environmental monitoring
> From: Eric Swenson <eric at>
> To: linux-poweredge at
> Organization: Reaction Engineering INTL
> Date: Tue, 11 May 2004 15:53:59 -0600
> Gentlemen,
> A little off-topic, but I'm looking for a decent setup to perform
> environmental monitoring in my small server room, as the HVAC tends to
> fail suddenly.  I need to protect my server equipment (PE4600 w/ RHEL ES
> 3.0) along with a small linux cluster in the same room, to the point of
> automatically shutting down specific equipment as the temperature rises.

I can't address the APC hardware/software, but I'll suggest one of the
things we've done....

We have an Omega circular chart recorder that measures and charts 
temp and humidity (

This unit has setpoints for alarms (high/low temp and humidity) and a contact
closure on the back to be hooked to an external device.

I've hooked the contacts up to a serial port (in my case on a Sun, but Linux
would work the same way) and wrote a tiny monitoring script that checks to
see if the contacts are closed (alarm condition). (It's a small, 100 line 
C program that is called by a script by a cron job that runs every 5 or
10 minutes.)

In my environment, this goes to paging software that sends a page
that the computer room temp/humidity are bad...  You could just as well 
take the output of this program and trigger the APC Linux software
(mentioned by others) to shut off various computers at the UPS 
(this does work - I've used it).

 Cristopher J. Rhea                     Mayo Foundation
 Research Computing Facility             Pavilion 2-25
 crhea at Mayo.EDU                        Rochester, MN 55905
 (507) 284-0587                        Fax: (507) 284-5231

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