If any single failure means people die you are doing it wrong. The way to live on mars is to dig a bug tunnel network with a lot of redundancy and have robots build everything on or under the surface. Sure, this means the only thing you notice is lower gravity, but frankly people are well adapted for earth and poorly adapted for every other place we know of.

Sci-fi loves the idea of domed city's or little domed greenhouses, but frankly Mars is to cold for this to work out. You need to waste a lot of energy to keep stuff on the surface warm and deal with a lot of nasty radiation long term.