The single biggest failure point for any network is its power supply. If you don’t have power, you can’t run your computers. This seems pretty obvious, and most of us slap an uninterruptible power supply (UPS) on the order when we’re buying a new server, or we at least make sure that the current UPS can handle the extra load. However, this barely scratches the surface of what you can and should do to protect your network from power problems. You need to protect your network from four basic types of power problems:
Local power supply failure. Failure of the internal power supply on a server, router, or other network component
Voltage variations. Spikes, surges, sags, and longer-term brownouts
Short-term power outages. ...