Sub-optimal way of creating replicas

[greg0ire]

During yesterday's troubleshooting I mentioned in #134 with @julienpa and @godelized, they told me changing the primary to add replicas one by one was not the best way to proceed and had significant overhead. They hinting that one should gather the names of all replicas and perform a single set settings call on the primary. I don't have all the details, but they will comment on this issue.