On Wed, Dec 10, 2014 at 09:42:43AM -0500, The Wanderer wrote: > On 12/10/2014 at 06:10 AM, Andrei POPESCU wrote: > > > On Mi, 10 dec 14, 07:32:07, Renaud OLGIATI wrote: > > > >> In my case no, more likely during shut-down, since the only time I > >> shut down my box is when there is a power cut, and I have to shut > >> it down quickly, before the UPS gives up. So I certainly do not > >> want an unwanted automatic fsck at that time. > > > > That would be easy to implement, assuming you computer "knows" it's > > running on batteries. > > On batteries is easy enough, for a laptop-style system. > > But for a more ordinary desktop (or server), running on a UPS, how is it > supposed to know that it is on battery-based power? > > It's plugged in through an ordinary power cable, with no other > connection to the power source. What indication is it supposed to have > that the power source at the other end of that cable is any different > from a standard wall outlet? > > I imagine that this might be one of the things the "USB cable from the > UPS" is intended to address, but I don't think my own UPS (for example) > includes any USB port, despite being a fairly high-end unit. (And off > the top of my head I don't know of any software to handle that in > Debian.) > NUT and APCUPSd are the most obvious solution > > For that matter, what if the wall outlet is connected to a "room" UPS? > There won't be a data connection to the UPS there. NUT caters for this situation. One machine is connected directly to the UPS (with a USB or serial cable, for example) and runs nut-server. The other machines run nut-client and listen for the notification that the server machine has switched to batteries. > > Or if the entire thing is backed by a building emergency generator? A generator is refillable so should, in theory, provide ample time for any clean shutdown. Fine, you *could* extend the problem to include the exhaustion of fossil fuels, the supernova of the sun and the inevitable heat-death of the universe, but at some point you reach enough notification that some one can get a keyboard on the machine and type "sudo poweroff". > > Both of those latter situations are similarly time-limited, and even if > there are heuristic solutions for the others, the last at least will > generally not be something the computer can detect and identify. > > -- > The Wanderer > > The reasonable man adapts himself to the world; the unreasonable one > persists in trying to adapt the world to himself. Therefore all > progress depends on the unreasonable man. -- George Bernard Shaw >
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