There was an event when a startup I was at asked Basho (they were the company behind Riak db) about backing up our data. Backing was a little side-feature that was possible to rig up, but I recall they looked at this inquiry as if I had two heads -- as if to say, it's replicated, why jump the shark? There was a bug with one of the Riak releases, and all the data was lost. (When we scaled up with this buggy Riak release, the empty node assumed master roll, and all the child nodes went, ah... the new state has no data, let's all delete records 0..k. Fun times.)