[Nut-upsuser] how to use multiple UPS with timers

[Roger Price]

On Tue, 8 May 2018, Steffen Grunewald wrote:

> I personally dislike timers.

I get the impression that the majority of people on this list dislike timers, 
since their use suggests that the shutdown plan ignores a basic feature of a UPS 
unit, which is the [OB] status.

Where I live, frequent lightning strikes can cause repeated power failures 
during a storm.  The same situation exists if the power utility is unreliable. 
In this situation, it is better to shutdown quickly keeping enough energy in the 
battery for a power return and then another power failure during the storm.

I see a difference between a « managed shutdown » and an « emergency shutdown ». 
A managed shutdown is an unfortunate, but regular occurrence, which should be 
well within the capacity of the UPS unit.  An emergency shutdown means that not 
only has the power utility failed, but the UPS battery is exhausted.

The managed shutdown uses timers, but the emergency shutdown on [OB] is always 
present, ready to take over if the number of power failures overwhelms the UPS.

Timers also make it possible to run a "heartbeat" through the NUT system. In a 
box which can be running for months, I like to be assured that the normally 
quiet NUT is running correctly.  For me, a "heartbeat" should be a part of every 
shutdown plan.

Roger