[kwlug-disc] UPS Power Down Question

[Cedric Puddy]

Hi All!

Unless there is a specific known thing that is a known risk in a power loss
event, I just let 'em die when the UPS gives up the ghost.  When the UPS
comes back online, they boot back up, and life goes back to normal.
 Messing about with auto-shutdown, and then restarting, generally means
more brittle config, higher likelyhood of being down until you are
physically there, and all for what -- you would have been down anyway, and
if there was no reasonable chance of damage, then why add that complexity?

I particularly dislike the situation where the server shuts down, the load
on the UPS drops, and then the UPS never *actually* loses power, since it's
got no real draw on it anymore.  Now the strategy needs to
accommodate reaching back into the downed server and starting it back up
again, or you have to go there.  Yay.

Small UPSs on small systems are to avoid inconvenience of unexpected
reboots from blips, and to ensure clean power (a decent line-interactive
UPS, presumably).  I've had enough issues with dirty power glitches over
the years that the power cleaning and filtering is more important to me
than power loss protection (though I certainly like having that!).

On the other hand, putting effort into ensuring you can put a bullet into
your system anywhere, any time, and still have it recover nicely on
restart, is the sort of thing that pays long term dividends.  Unless you're
doing retro-computing stuff, why run databases, filesystems, etc, that
aren't durable in the face of a sudden restart?  What is making you run
systems that care what order they come up in?

There are certainly limits to this strategy, but it has served me well with
small things for a long time.

  Hope that helps,
  -Cedric

| CCj/ClearLine - Hosting and TCP/IP Network Services since 1997
| 118 Louisa Street, Kitchener, Ontario, N2H 5M3, 519-489-0478x102
\________________________________________________________
  Cedric Puddy, IS Director cedric at ccj.host


On Sun, 24 Nov 2024 at 17:26, Khalid Baheyeldin <kb at 2bits.com> wrote:

> I finally have a working configuration for NUT.
>
> I could not get upssched.conf working with custom timers
> (e.g. start a timer on ONBATT, then cancel it when ONLINE).
>
> But I did get the other features working like this (ups.conf)
>
>   ignorelb
>   override.battery.runtime.low=900
>   override.battery.charge.low=15
>   override.battery.runtime.restart=60
>
> That will shutdown the server if there is only 15% remaining
> charge in the battery, or 15 minutes.
>
> The one thing that is not to my liking is this: when these
> conditions are met, the server will shutdown (as I want it
> to), but it also shuts down the UPS.
>
> Is there a way to shutdown only the server, and leave the
> UPS running until the battery is drained? That way internet
> access will continue with the router and modem powered.
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