You are not necessarily doing it wrong, you may simply not have enough ressources ($$$) to buy enough hardware for complete redundancy.
When you get evicted from an EC2 instance you just switch to a new one, the cost is constant. When your piece of hardware at the datacenter goes down, unless you had the ressources for a spare one, you are hosed.
When you get evicted from an EC2 instance you just switch to a new one, the cost is constant. When your piece of hardware at the datacenter goes down, unless you had the ressources for a spare one, you are hosed.