nanog mailing list archives

Re: Power cut if temps are too high


From: Mel Beckman <mel () beckman org>
Date: Mon, 27 May 2019 18:18:08 +0000

We use Intermapper, an SNMP network monitoring system, which supports UNIX scripting. Intermapper probes two 
Weathergoose temperature sensors, and calls a script with the values it retrieves. When both sensors exceed a certain 
threshold, the script sends an snmp relay trip signal to the Weathergoosen, which close a pair of dry contacts wired in 
series to the emergency power off contacts for the whole-room UPS.

We chose to use two sensors and two dry contact relays to protect against false trips, and thus false shut downs. 
Before the trigger temperature is reached, the NMS would have sent various escalating alarms to on call staffers, who 
hopefully would intervene before this point. This protection is for the worst case scenario where nobody responds and 
the equipment is at risk of damage.

We could have commanded an orderly shut down to all servers, but decided that it would be better to kill the power in 
the event of a runaway heat vent than to try to make it through all the disk activity necessary for a clean shut down.

This system has triggered one time, successfully shutting down the data center on a holiday weekend when people missed 
their notifications, and undoubtedly saved a lot of hard drives. When we got to the room the temperature was over 115°, 
but the power was cut at 95°.

 -mel

On May 27, 2019, at 11:01 AM, Dovid Bender <dovid () telecurve com<mailto:dovid () telecurve com>> wrote:

Hi,

Is anyone aware of a device that will cut the power if the room goes above X degrees? I am looking for something as a 
just in case.


Regards,

Dovid

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