On 3/25/2012 2:39 PM, Timothy Murphy wrote: > Ryan Wagoner wrote: > >> Additionally if your computer BIOS supports configuring the AC recovery >> power mode to always on, the computer will start back up. Most default to >> last state, which doesn't work as well since shutting down will power off >> the computer, which means that last state is off. There are some >> workarounds to change the shutdown sequence to just halt and not power > Thanks again for your response. > I did an experiment which I probably should have done before, > to find out exactly what happens if the power is cut off, and then restored. > You were completely correct. > > My server is an HP MicroServer (running CentOS-6.2). > If the machine was running before being cut off > then it reboots normally when power is restored. > If however it is shutdown before the power is cut > then it does not reboot when power is restored. > As you say, it always returns to the state it was in when the outage occurs. > > I looked in the BIOS, but there is no option on this machine > to change that. > > So I shall know what to do when I get a UPS. > If there is no better setting I can just allow the UPS to become exhausted > if the outage lasts longer than the life of the UPS. > > in the apc software(or nut worst case) you'll be able to specify that after x minutes it will shutdown. Better to have a clean shutdown and have to hit the power button than a dirty one and risk corrupting your filesystem.