[ceph-users] Achieve no loss-of-write with 2 node failure?

I've been trying to wrap my head around avoiding loss-of-write with a 2-node failure with erasure coding. If I set min_size=k+1, does that mean I'd need a minimum of m=3 to avoid loss-of-write with a 2-node failure? And to avoid loss-of-write with a 2-node failure, would I need: a) a minimum of k+m nodes, or b) a minimum of k+m+2 nodes? If the answer is k+m nodes, would I want to go with k+m+2 nodes anyway for other reasons? Thanks. Andrew