On Wed, 5 Oct 2016, Jeff Bowman wrote:
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?
Yes.
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.
The command is "upsdrvctl shutdown".
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.
The 300 seconds start when the effect of "upsdrvctl shutdown" reaches the
UPS hardware. See the diagrams at
http://rogerprice.org/NUT.html#SYSD_RACE which assume an offdelay of 20
seconds.
Roger
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