The UPS and the diesel generator are 2 devices for keeping a server functioning if there are troubles with the primary power source - a disruption or unstable current that can't keep the server working correctly, for instance. UPS is an abbreviation for Uninterruptible Power Supply, although it is sometimes called Uninterruptible Power Source as well. The UPS is, basically, a powerful battery that's connected to the hosting server and to the electric power network all the time, so in case there is any blackout, it is already functioning, which allows the web server to carry on operating without losing any info. The diesel generator is an engine that will power up an entire data center. It does take some time to begin working and it's the UPS that provides that time. These 2 power solutions are absolutely essential for any facility or service provider that wants to prevent information loss and hardware damage resulting from an unexpected electrical power issue.