[Nut-upsuser] MGE pulsar evolution 3000 discharges without nut noticing

[Aaron J. Grier]

On Wed, Feb 20, 2008 at 09:28:15AM +0100, Arjen de Korte wrote:
> > the bad news is that nut completely ignored that the UPS was
> > discharging, and none of my connected machines shut down properly.
> 
> It didn't ignore it, the UPS just wasn't critical at any time during
> this test. By default, NUT will only start a shutdown sequence when
> the UPS becomes critical (ie, no input power available and batteries
> low). From the above, I conclude that at no time the input power was
> lost and neither the batteries were low. You have a couple of things
> to configure to make NUT behave otherwise.
>
> [NUT] was reporting [OL DISCHRG] all the time. There was just nothing
> NUT needed to do.

that's the mystery.  this was a critical situation not recognized by NUT
as such.  power _was_ cut to my machines shortly after 06:34.

> > why did my UPS decide to discharge its battery when there appears to
> > be no power outage? (just looking for suggestions and guesses here
> > from other MGE users...)
> 
> Most probably, because of an (automated) battery test. Or someone
> initiated one, but given your surprised reaction, I guess it wasn't
> you.

this situation has not occured in the five+ years I have owned the UPS,
although I have been through a number of power outages.

after discussions with a co-worker who worked for MGE during the
development of the evolution UPS series, the current theory is that the
battery charging circuitry failed during a self-test, and the charging
circuitry was not re-enabled until after the batteries were completely
drained and the UPS power-cycled itself.  NUT did not recognize this
condition as critical, although there appears to be enough information
for it to have done so.

other conditions of [OL DISCHRG] occur within context of full outages
followed by [OB DISCHRG], or sporadically when upslog catches a
self-test in progress.  neither of these are critical events.

> > why did nut not see that my UPS was discharging and the battery
> > percentage running down and take appropriate action?  "OL DISCHRG"
> > status in the logs seems nonsensical.
> 
> This is all documented (in the FAQ for instance). This makes perfect
> sense.

I do not understand why the UPS dropped power shortly after 06:34.  I
will be in touch with MGE regarding this.

I do not understand why NUT did not recognize the extended [OL DISCHRG]
situation as critical.  that is why I'm here on the list asking
questions.

> > ups.test.interval: 10080
> 
> There you go. This seems to be an awful short interval (three hours).

this has not been changed from the default, and I'm unclear what
relevance this interval has to NUT not recognizing my situation as
critical.

> Again, read up on the FAQ and come back if you anything is not clear
> to you.

[ re-reads the FAQ at http://www.networkupstools.org/faq/ ]

> Q: Why doesn't upsmon shut down my system?  I pulled the plug and nothing
>    happened.
>
> A: Wait.  upsmon doesn't consider a UPS to be critical until it's both
>    'on battery' and 'low battery' at the same time.  This is by design.
>    Nearly every UPS supports the notion of detecting the low battery
>    all by itself.  When the voltage drops below a certain point, it
>    _will_ let you know about it.

this FAQ addresses the [OB DISCHRG] condition, which NUT correctly
recognizes as critical.  I ran into an extended [OL DISCHRG] condition,
which NUT does not recognize as critical.

I believe this to be in error, and a potential bug with NUT.

would a patch to NUT to recognize the combination of [OB DISCHRG] and
low battery as critical for this UPS model be accepted?

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier at poofygoof.com