Re: Too hard, too frequent, too unreliable
2 (or more) sets of machines is a good idea. The trouble comes when you need to upgrade or replace one set and the beancounters notice that the system only switched to that set once or twice in the year.
You can bet if that happens, they’ll be asking why you need the machines.
You can usually persuade them by telling a horror story about what would happen if the only machine left running the system failed..