I am not too sure if the term ‘defense-by-redundant-systems’ is the right term since, well, we design station utilities network the same way we design utilities network for our cities.
The basic flow of water and electricity goes this way: source -> station -> main -> periphery
Illustrating this principle in the context of a habitat-class space station, using power distribution as an example, it would be ‘nuclear reactor -> transformers -> main conduits -> branch conduits (-> homes/shops/etc)’.
We lay down the main conduits in our cities underground. The same idea is applied to stations, except instead of underground, we run them through the ducts. The branching wires are extended from these main conduits, out from the ducts and into wall wiring, then to the homes/shops/etc.
Apply the same principle to plumbing and oxygen.
However, considering that we do not need wires to distribute air and we do not need to distribute air to every individual home, etc, we run the ventilation system through the ceilings and distribute the air wholesale everywhere in that particular sector.
So, there is redundancy by design, it is an efficient distribution system and it is proof against total shutdown caused by stray gunshots and hammer-blows. Kill three corovids with one bullet, as it were. Then we jerry-rig all manner of crap & make a mess of things.