[Nut-upsuser] UPS Shutdown

[Jeff Bowman]

I'm trying to better understand OffDelay and OnDelay:

http://networkupstools.org/docs/man/usbhid-ups.html#_extra_arguments

My server requires ~3½ minutes to shut itself down. Considering this I'm comfortable setting OffDelay to 300 (five minutes).

How does this work in conjunction with the UPS hardware? Does NUT immediately send a command to the UPS to wait for 300 seconds and then shut itself down, thereby allowing the server enough time to safely shut itself down as well?

This is the only way I can think of that the arrangement can work. As it's naturally impossible for a turned-off computer to send any command anywhere, an option for sending a "take-this-now-but act-on-it-later" command surely must exist.

I'll be initiating my own shutdown sequence as a result of NOTIFYCMD with a NOTIFYTYPE of ONBATT. My process will poll battery status for five minutes (to reduce false positives) before finally deciding to send individual shutdown commands to the server, NAS, other devices, etc. In other words, I'm going to write my own upssched, suited specifically to my platform and configuration needs.

Given this configuration, at what point will the 300 seconds start counting down? What trigger sends the actual command which in turn tells the UPS hardware to start that countdown? The documentation is unclear on this finer point.

Thanks,
Jeff Bowman
Fairbanks, Alaska

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