Devin Reade wrote:
> There is one flaw that I know of with APC brand UPSes, although I wouldn't
> be surprised if other UPSes are similar (since APC has traditionally
> set the standard in the market): There is a small window between
> the time that the UPS initiates a shutdown and the control software
> (such as apcupsd) tells the UPS to kill power in (some number of) seconds.
> If your mains power returns and stays on during that window, your
> machine may not restart by itself: It may be too late to cancel the
> OS shutdown and subsequent power-off, but because the UPS still has
> mains power it doesn't trigger the power cycle that allows the computer
> to reboot (assuming you've configured your BIOS to boot at power-on).
> In my experience this doesn't happen often (I've seen it probably
> twice in 15 years), but it does happen and can be a real PITA if
> you don't have anyone on site that can deal with it.
This can be solved with several approaches.
First is to have LAN power controller/switch, can't remember how you
call it. It can monitor several inputs like voltage, on/off, etc, and it
can be used to cut and restore power, as well as reboot. They have web
interface and are accessible via IP. Wireless network guys use them.
Another approach is to have power switch power by mobile/cell phone. You
call the number and it effectively cuts power for a desired period of time.
Ljubomir
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