today again a post out of my daily business. When I’m out in the field and I plan a new cluster, I also need to decide how many and what type cluster redundancy I need to implement. For that I have some thing like a blueprint or decision matrix in my mind which I leverage.
Today I want to give you a small view into this matrix. 🙂
When to choose a redundancy where only one or two cluster nodes can fail?
That is the most common and easiest why for node redundancy in a cluster. It means you have enough nodes in your cluster to cover one or two node failures. You would choose that cluster config when all of your nodes are in one datacenter or server room and you have no additional space or need to replicate your virtual machines.
When to choose a redundancy where you can choose half of the nodes?
In this scenario you can lose one half of your nodes but you need to fulfill some more requirements like storage replications or direct WAN links. You would normally use if you want to keep your services alive if one datacenter, server room or blade center fail.