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.

Everyone is vulnerable to outages caused by storms and other natural phenomena and must protecting both of its software and hardware.

Uninterruptible Power Supplies does three things for you. First, it filters the power your machine sees, smoothing out spikes and voltage fluctuations that can stress or even damage your electronics. Secondly, it provides a certain amount of dwell time in the event your power goes out entirely — this can often get you through brownouts and short blackouts. Third, when the UPS is about to run out of power it can arrange a graceful shutdown of your computer so that no unpleasant things happen to your disk filesystems.

Here's what a UPS will do for you:

• Absorb relatively small power surges.
• Smooth out noisy power sources.
• Continue to provide power to equipment during line sags.
• Provide power for some time after a blackout has occurred.

In addition, some UPS or UPS/software combinations provide the following functions:

• Automatic shutdown of equipment during long power outages.
• Monitoring and logging of the status of the power supply.
• Restart equipment after a long power outage.
• Display the voltage currently on the line.
• Provide alarms on certain error conditions.