For the last months Kyle Kingsbury, a.k.a @aphyr, as been working on a series of blog posts and talks around the consistency guarantees of distributed systems. It's a monumental piece of work that shows that what these systems claim to guarantee is not always true in reality. He's tested Redis, MongoDB, Cassandra, Kafka, Riak, Zookeeper and a few others.
Let's meet and talk about his findings. You can read all of the blog posts and find more information at http://aphyr.com/