[Nut-upsuser] UPS shutdown - always the thing to do?

Mark E. Hansen meh at Winfirst.Com
Tue Nov 20 15:17:01 UTC 2007

On 11/19/07 18:28, Whit Blauvelt wrote:
> Now looking at the FAQ again, it offers the same snippet of code as the
> Install doc, but implies that it isn't needed just in case the bios - as
> mine does - has an "always power on when power's restored" option. 

I don't see how that will help...

> If that implication is right, then does that mean that soon after the UPS
> gives the signal to the PC that the PC should consider shutting down, that
> the UPS will cut the power anyway - assuring a power cycle to restart the
> PC?

That is not my experience. However, I think there are some UPSs out there
that will kill the power to the PC automatically after some delay. From
my testing, the CyberPower AVR1200 that I use does not do this.

>      If so, that could leave a small window between the PC's going off and
> the UPS cutting the power (when not commanded to do so prematurely with that
> "shutdown" command) in which power restoration wouldn't trigger the PC
> rebooting - unless the UPS is smart enough to power cycle on power
> restoration just in the case that it was past the point of advising PC
> shutdowns already. If that's so, then I should stop worrying and get back to
> packing for vacation.

I think to make this work, you're going to have to tell the UPS to kill the
power to the PC. Without that, you don't have any way to tell the PC to boot
back up (unless, of course, the UPS battery goes dead before the line power
is restored - I don't want to depend on that).

> (I'm not, btw, really expecting you know this level of detail - just figuring
> someone on this list probably does. The docs seem to not quite cover this.)

Well, as I've said, I'm not an expert. I've just recently gone through this
with a CyberPower AVR1200 connected to a CentOS 4.5 (RedHat Enterprise Linux)

Good luck.

> Regards,
> Whit

Mark Hansen, PP-ASEL, Instrument Airplane, USUA Ultralight Pilot
Cal Aggie Flying Farmers
Sacramento, CA

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