[plug] UPS PowerShield "Restart"

Bernd Felsche berfel at innovative.iinet.net.au
Sun Apr 5 10:43:06 WST 2009

Tim White <weirdit at gmail.com> wrote:

>I'm looking at getting the Powershield Defender UPS's from PLE to help 
>my computer ride through the silly little power glitches that seem to 
>kill the computer without resetting it. I have in the BIOS the setting 
>to restart the computer after the power has been disconnected. What I'm 
>hoping for with these UPS's, is the ability to shutdown a machine 
>cleanly, and then when the UPS is back on AC power, to restart the 
>computer. Does anyone know if it's possible with these UPS's, or have it 
>working? Otherwise, I'd forgo the shutdown and instead just have the 
>computer cleanly "shutdown" parts of it, like NFS and remount the 
>harddrives read only, and allow the UPS battery to run down, so when the 
>power is restored, the BIOS will bring the computer back up as per normal.

The UPS monitoring software monitors AC mains as well as battery
state. Software should ideally react accordingly; like it does on a
laptop when running on main vs battery. e.g. go into "power save"
mode when running on UPS battery and a clean shutdown when the
battery gets to the last 2 minutes or so of reserve. (Keep in mind
that shutting down requires significant system activity.)

>p.s. This is all for a Linux box, which these UPS's are supposed to have 
>software for, any comments on the included Linux software?

Try it with "nut".

The supplied software is probably the UPSilon that was appropriate
with a 2.2 kernel. (Tell-tale is the SCO Xenix "compatability".) It
makes too many assumptions on how the system should run that are now
far removed from modern Linux. IME; with other UPS in the past, it's
gotten itself into busy loops as well as failing to actually
initiate a shutdown at other times. i.e. it's quite clumsy in a
modern Linux system.
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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