Redundancy
Redundancy
A design technique that keeps a service running by switching to backup equipment when part of a system fails.
In Simple Terms
Redundancy means having backup equipment ready in advance, in case a system fails. For example, a company might run two web servers side by side, so that if one fails, the other immediately takes over processing. Setups like this are used in internet services and financial systems that need to keep running 24/7.
Behind the Name
The term comes from the English word "Redundancy," which means excess or duplication — having more of something than is strictly needed. That sense carries directly into the tech usage: extra components kept on standby in case the primary ones fail.
Take a Closer Look!
Redundancy means preparing extra backup equipment and connections in advance, so a system or network can keep running a service even if something fails.
Put simply, it's a strategy of doubling up on the parts that matter most.
An everyday example is carrying a spare tire in your car in case you get a flat. IT works the same way: servers, power supplies, and internet connections are all set up in multiples ahead of time.
By keeping things ready to switch over to a backup the moment the active equipment breaks, you reduce the risk of the whole service going down. How fast the switch happens, and whether it's automatic, depends on how the system is designed. When it's built well, recovery can happen so quickly that users barely notice.
This approach is widely used anywhere that even a moment of downtime causes serious problems, like banking systems or online shopping sites.
It costs more to have all that extra equipment on hand, but it's an important design technique for keeping things running through trouble.