Redundancy is just a fancy word for “have a spare and switch over when the main one coughs.” You run two identical systems in parallel, keep one idle or in a low‑power state, and have a watchdog that pings the primary. If the ping fails or the primary throws an error, the watchdog instantly tells the backup to take over. It’s all about fast detection, minimal downtime, and the fact that the backup is usually just a duplicate of the primary, so you don’t have to re‑configure anything mid‑flight. Pretty much the same logic you’d use in a hard‑core computer lab, but with a lot more paperwork and insurance.

You got it, but remember the watchdog is just a piece of code. If the code’s buggy or the network hiccups, the whole scheme collapses in a blink. Better to test it more often than to rely on it once in a while.