Replicas in 2 node cluster, single document occurrence instead of double

I’m running (development mode) a cluster with 2 node 4 buckets ~~300k documents total.
couchbase community edition 4.5
I’ve set number of replicas=1 as no more is possible with only 2 nodes.
If i turn off one node I can only see HALF of my document available in the remaining node…I cannot understand what I did wrong in setting up the cluster and how can I set it to replicate each document on both nodes.
thanks in advance