[Nut-upsuser] APC Smart UPS at a Mac Mini

Charles Lepple clepple at gmail.com
Mon Aug 29 12:57:26 UTC 2011

On Mon, Aug 29, 2011 at 7:14 AM, Wolfgang Hottgenroth
<wolfgang at hottgenroth.net> wrote:
> I'm using a APC Smart UPS with a Mac Mini, connected using a USB serial converter.
> Works fine so far, the Mac Mini will be shut down, a NAS connected of the network to the nut on Mac Mini will also shut down, perfect.
> However, the ups will not be shut down. Very unfortunate, since the Mac will not start again, if the power comes back before the batteries are completely empty.
> I read about /etc/killpower and a may be required modification of the shutdown script.
> But there is no such script in Mac OS X Snow Leopard.

I admit I haven't investigated the OS X shutdown sequence much - my
main OS X box is a laptop, and the Mac Mini isn't doing anything

I think that the built-in USB UPS support simply commands the UPS to
shut down after a delay. I think there's a potential race condition
there if the power comes back on as you described, but maybe the APC
UPSes avoid that by power-cycling the load if they have already been
commanded to shut down when the power returns.

Can you post your shutdown command, and the output of "upsc", "upscmd
-l" and "upsrw" for that UPS? No need to include ups.serial if you
don't want to post the serial number - I'm mainly interested in the
firmware version, NUT version, and what commands and variables are
detected as supported by the apcsmart driver.

Michal Soltys has made some improvements to the APC shutdown support
recently, so he might be able to offer some suggestions about using
the delayed shutdown feature with your hardware.

- Charles Lepple

More information about the Nut-upsuser mailing list