My ups does neither of those things -- power fails, ups stays on till I shut everything off, or battery runs out. So for those one second outages, it works great machines never go down at all. Gregory Nowak <greg at gregn.net> wrote: > Hi all, > this is primarily aimed at those here who have UPS (uninterruptable > power supply) battery backup units. I seem to recall Kirk has one, and > maybe others here do as well. > > We have a power outage here every 3-4 months, lasting anywhere from > one second to close to 3 hours so far. So, I had been thinking of > getting a UPS some day for a while now. According to my > server/router's uptime, our most recent outage happened 36 days ago, > and it lasted for a second, if not less. Everything including clock > radios and stove clock seems to have survived it, except for the > server. The fans and drive stayed on, but the machine was > unresponsive, forcing me to power cycle it. That's when I decided that > this happens frequently enough, and is annoying enough to maybe turn > some day into in the near future. > > Until I researched UPS units, my idea of how they work was perhaps too > idealistic. Power fails. Server properly shuts down. Power comes back > on, server starts up. I found out though that this doesn't seem to be > exactly how things go though. > > My server is setup in bios to turn on whenever power is applied. My > research seems to indicate that there are two extremes as far as UPS > units go. In the first extreme, power fails, the server shuts > down. However, since the UPS isn't fully drained, the power from the > UPS stays on, and the server doesn't start back up when the power > company gets their act together, and utility power comes back > on. That's fine if someone is around to press the power > button. However, what if when this happens everyone here happens to be > on a longer vacation? > > In the second extreme, some UPS units are set to cut power, and > reapply power again about a minute after utility power comes back > on. If the server shuts down before utility power comes back on, > that's good. If utility power comes back on before the server shuts > down, then the UPS causes the very problem it is supposed to > prevent. This leads me to conclude that they're worth getting if one > has a backup generator, or power outages tend to be short, and the UPS > unit doesn't cycle the power. > > I also question the value of a proper shut down these days. Before > journaling file systems, an improper shut down was a headache. Now > though, it doesn't seem to be such a big deal. I've been through power > failures maybe ten times now, and every time so far, the journals were > recovered, and the system fully booted up, and was ready for prime > time without my intervention (except in cases of split second > outages). On the other hand, when we were having some electrical work > done recently, I asked the electrician to wait for me to shut down > the server before he cut the power, instead of just letting him cut > power whenever he was ready. > > To keep this somewhat on topic, since the server only has USB ports, > and no serial port, I was concerned about the compatibility of USB UPS > units with gnu/linux. Based on reviews, the unit I would get if I > decide to get it seems to be compatible with gnu/linux using USB to > communicate: > > http://www.newegg.com/Product/Product.aspx?Item=N82E16842101311 > > Finally, though not strictly necessary, I can't help thinking that it > would be nice to power my dsl modem, network switch, wifi access > point, server, and maybe charge other battery devices during a power > outage for a while. I'm also wondering how hard it is to find > replacement batteries locally or on-line? While I see UPS battery > backup units on newegg, I haven't yet found a category with > replacement batteries for them. The reviews seem to indicate that new > batteries run for about $30 U.S., so that isn't bad, if I only knew > I'd be able to find them in order to buy them. > > So for those of you who have these units, are they worth it, or are > they maybe less valuable to have than in the past? Thanks for any > comments. > > Greg > > > -- > web site: http://www.gregn..net > gpg public key: http://www.gregn..net/pubkey.asc > skype: gregn1 > (authorization required, add me to your contacts list first) > > -- > Free domains: http://www.eu.org/ or mail dns-manager at EU.org > _______________________________________________ > Speakup mailing list > Speakup at linux-speakup.org > http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup -- Your life is like a penny. You're going to lose it. The question is: How do you spend it? John Covici covici at ccs.covici.com
