Date: Thu, 9 Mar 2006 17:19:45 -0500 From: "Bob Johnson" <fbsdlists@gmail.com> To: "James Long" <list@museum.rain.com> Cc: freebsd-questions@freebsd.org Subject: Re: coming back up after power failure (UPS) Message-ID: <54db43990603091419n73d44758ne475fc920848e43c@mail.gmail.com> In-Reply-To: <20060309200708.GA15255@ns.museum.rain.com> References: <20060309174609.GA14114@ns.museum.rain.com> <MIEPLLIBMLEEABPDBIEGKEBHHEAA.fbsd_user@a1poweruser.com> <20060309200708.GA15255@ns.museum.rain.com>
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On 3/9/06, James Long <list@museum.rain.com> wrote: > > You missed the point. > > If the system does NOT power itself down, but instead sits at the > "press any key to reboot" prompt, then playing with the NUT configuration > isn't going to improve anything in cases where power returns before > batteries are drained. The OP would have to troubleshoot his inability > to get the machine to power off upon a line outage, which it appears > he has done. To extend on what you said: after the PC shuts itself down, the UPS is still providing power. If the UPS returns to line power before the UPS shuts down, the PC BIOS never sees a power down event, so it doesn't know to turn the system back on. One solution to this is as follows: - When the UPS believes it is about to run out of battery power and shut down, the OS shuts down to single user mode and starts a script that will reboot the system in five minutes (or long enough to be sure the batteries will run down first). - If the UPS does shut down, when power is restored, the BIOS will detect the event and power up the PC normally. It will boot as normal. - If the UPS never shuts down (because line power is restored) the script eventually times out and reboots the system anyway. I tried to make this work a few years ago, but could find no way to start a script after shutting down to single user mode. I posted a query about it but got no replies, so I quit worrying about it. I've since seen some hint that it is now possible to do that, but I didn't follow it up. Can anyone tell me how to do that? Another solution is a UPS that always shuts down after it has notified the host OS that it needs to do so, but that's not something NUT can count on. - Bob
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