What is a UPS?
An uninterrupted power supply (UPS), also known as a battery back-up provides emergency power and, depending on the topology, provide line regulation as well to connected equipment by supplying power from a separate source when utility power is not available. It differs from an auxiliary power supply or standby generator, which does not provide instant protection from a momentary power interruption. A UPS, however, can be used to provide uninterrupted power to equipment, typically for 5-15 minutes until a emergency power system can be turned on or utility power is restored.
While not limited to safeguarding any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption or data loss. UPS units come in sizes ranging from units which will back up a single computer without monitor (around 200 VA) to units which will power entire data centers or buildings (several megawatts).
The above was taken directly from wikipedia.org
What kind of UPS should I purchase?
Fonality makes no official recommendation endorsing any specific UPS manufacturer or product, but we can provide you with a link to a consumer-UPS selection guide and UPS explanation that should guide you in your decision-making process.
Please read http://www.smps.us/uninterruptible-power-supply.html
How should I implement a UPS?
Most UPS devices act like power-strips turning a single power outlet into multiple outlets where the power from the wall travels through the UPS device and powers all of the other equipment connected.
Therefore, it's pretty easy to install a UPS with very little downtime for your system.
Connect the UPS to an available outlet.
Consult the UPS device's user manual in order to reference the meaning of any status lights on the device. Most devices will have a green LED light that turns on when the UPS is operating correctly. Before you connect any equipment to your UPS, use these status lights to verify that the UPS is fully operational and prepared to power other equipment.
From a keyboard and monitor attached to your server, login as root
Type shutdown -h now from the root console
The system should display a number of shutting down messages to the console. At the very end of this output, the system will say Power Off
At this point, please turn off the power to the system. Either press the rocker switch on the back of the box, or press the power button on the front (it depends on the type of system you purchased)
Connect the power cable from your server to an available outlet on the UPS
If there are status lights indicating a successful connection, verify these lights turn the appropriate color indicating no issues with the UPS power port (the light will typically be green on most devices)
Once you have verified that the physical connections are good, power on your server again.
Your server should boot normally. Try to make a test call from one of the phones in your office to an outside number to determine if everything is operational once again (allow the server enough time to boot before you try to make a call - making a call immediately after you press the power button will naturally fail as the server will not have completed it's boot sequence)