As a social marketplace, Copious incorporates a blend of data models, each with its own constraints and operational challenges. Activity streams, social context, product search, and purchase processing span the spectrum from absolute consistency requirements to "any response is better than no response." Rather than trying to find one db to do everything, we've embraced a multi-datastore approach. With some great results and the odd epic fail.
In this talk, Copious Co-founder Rob Zuber, discussed what data stores they use and how they selected them, what's working well and what isn't, and where Riak fits into the stack. He also talks about specific use cases in their environment including both development and operational concerns.