An Uninterruptible Power Supply (UPS) is an important thing to have if you live in an area where power outages are at all common, especially if you run a mail/DNS/Web server that must be up 24/7. The aging power grid in the U.S. has made this a more urgent issue than it used to be even for American hackers, but everyone is vulnerable to outages caused by storms and other natural phenomena. This document covers both the software and hardware aspects of protecting yourself.
The advice in this document is aimed primarily at small installations — one computer and one UPS. Thus we'll focus on consumer-grade UPSes, especially those designed for home and small-business use. If you are a data center administrator running a big server farm, there is a whole different (and much more expensive) range of technologies we'll do no more than hint at here.
The people who contribute to this document can speak only about equipment they have experience with. This may reflect a bias toward or against certain brands, features, functions, etc. Please keep in mind that the suggestions, brand names and functions here are by no means exhaustive, or even necessarily applicable to your situation. Also, if you have information that is not in this document, please submit it to the maintainer listed above. If you submit information, please say whether you'd like it to be attributed to you or not. We are more than glad to give credit to the fine people who helped with this document, but we want to respect the anonymity of those people who would prefer it.
You can also view the latest version of this HOWTO on the World Wide Web via the URL http://www.tldp.org/HOWTO/UPS-HOWTO.html.
Copyright (c) 2003,2006 Eric S. Raymond.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is located at www.gnu.org/copyleft/fdl.html.
Feel free to mail any questions or comments about this HOWTO to Eric S. Raymond, <esr@snark.thyrsus.com>. But please don't ask me to troubleshoot your general UPS problems; if you do, I'll just ignore you.