Bruno Wolff III wrote: > On Wed, Nov 14, 2007 at 16:20:56 -0800, > Konstantin Svist <fry.kun@xxxxxxxxx> wrote: >> Also tried to tackle the problem with power not coming back on its own. >> The problem appears when the computers shut off but a little bit of >> power remains in the UPS batteries. The computers have a BIOS setting to >> boot as soon as power is connected - but if the UPS is not drained, the >> power is never really cut, so the result is that they don't boot if the >> power comes back. > > nut handles this for most UPS'. There are some models that don't support > the proper command, but you can check for those before buying one. > It does this by having the UPS cut power to the load even though there > is still battery power. The command is issued with a time delay that is > supposed to give enough time for shutdown to complete after the command > is issued. > The scripts that control shutdown when using a UPS also tend to tell the UPS to shutdown as the last step. Even a "dumb" UPS that communicates using the RS-232 status lines normally monitor one of the output lines, and shutdown when the line goes high. This lets the UPS start when the computer is off, because the powered down state is low. Depending on the UPS, you may have to hit a reset button before it will turn on again, it may require the input power to be back and stable for a period of time, and/or the battery charge to reach a specific level. The better UPSs let you configure this. Also, most "smart" UPSs will also function as a "dumb" UPS. One thing to be careful of - if you are controlling more then one machine off the same UPS, using network communications to shut down the machines not monitored the UPS directly, is that once you start the shutdown, you have to complete it because the remote machines not longer have a way to know the power is back once they reach the point that they shut down the network connection. So you need to finish the shutdown even though power is back up. In other words, once the pf script is started, do not abort it. Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup!
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