Ciprian Marius Vizitiu wrote: > I've just read the FAQ and got to the question: "Q: How can I make upsmon > shut down my system after some fixed interval?" Well it looked like the > question was there for me. :-) > > You say: > > Ask yourself this: why buy a nice big UPS with the matching battery and > corresponding runtime and then shutdown early? If anything, I'd rather have > a few more minutes running on battery during which the power might return. > Once the power's back, it's business as usual with no visible interruption > in service. > > If you purposely shut down early, you guarantee an interruption in service > by bringing down the box.
I didn't say this, I was referring to the FAQ and the part that was right before your quote: > If your system has a really complicated shutdown procedure, you > might need to shut down before the UPS raises the low battery flag. > For most users, however, the default behavior is adequate. In my (private) reply, I wrote that you need to setup 'upssched', a remark you also conveniently left out. You never mentioned anything about repeating power failures. > Although this sounds like a well considered argument it doesn't account for > all situations. It's not uncommon in certain parts of the world to have > power outages one after another with a say... 2 minutes in between. The > power company does its best to restore power but the consumption is still > too heavy so they need "a bigger hammer" :-)... I've seen it happening. In a > situation like this things can get hairy. Let's assume the UPS has juice for > 25 minutes; let's assume it takes 40s to shut down and 1min 20s to boot. In > a scenario with the following events: "40 minutes power outage, power > restore for 2 minutes, power outage for 10 minutes, power restore" you might > end up having to manually say "Y" to fsck because the UPS has wasted all > juice on the first outage and there was no time to recharge the batteries > for the second outage... Chances are the machine is busy running scripts > before nut gets a chance to start and anyway the second power failure > strikes with no juice in the batteries. The other option is to shut down at > 10 minutes after the first event so you have some 15 minutes left in the > UPS; even if the second event comes right when the machine is booting there > is enough juice for the machine to complete a boot->UPS-Alert->shutdown > cycle, don't you think? Read 'docs/shutdown.txt', especially the last part, 'One more tip'. Best regards, Arjen _______________________________________________ Nut-upsuser mailing list Nut-upsuser@lists.alioth.debian.org http://lists.alioth.debian.org/mailman/listinfo/nut-upsuser