UPS

An uninterruptable power supply, or UPS, is strongly recommended. Even if it only able to keep the system up for five minutes before shutting down, it would be to your advantage to use one. Most power outages last less than a minute. The UPS will keep your system running through such power outages without interruption. If the UPS does go into the shutdown mode, it provides for an orderly shutdown. This will help guard against corrupting the hard drive due to a sudden removal of power while the drive is writing. While it doesn't happen all that often, a write during a power-down will always result in at least some data loss. Worse case would mean rebuilding the entire system from the ground up.

UPS's are available from numerous vendors. Before buying, be certain there is software support for Linux - specifically your flavor of Linux. This is most important. While the UPS will work without the software, it is impossible to get an orderly system shutdown without it. It will get you through most power glitches and short outages, but if the big one comes, you may lose data.

The author has and is using both Tripplite and APC UPS units. Both offer good reliable UPS's at reasonable prices and have software support for Linux. You should be able to get minimal protection for under $100. However, if you want long-term support for your system, look at the larger VA units that accept additional external batteries. A 4500 VA system can be had for around $400. That should keep things running for several hours.

Installation of UPS support software is not covered here since it has no direct connection with the WXN server suite. There are, however, several good sites that deal with Linux UPS support. The following list should be of some benefit:

http://www.exploits.org/nut/library/cables/
http://www.apc.com/?isoCountryCode=us
http://us1.networkupstools.org/
http://www.apcupsd.com/