Last time I talked about the key differences between RDBMS and the most important NoSQL databases. The key reasons why NoSQL databases can scale the way they do is that they shard based on the entity. The „simplest“ form of NoSQL database shows this best, the distributed Key/Value Store. Last week I had the chance to talk to one of the Voldemort developers at LinkedIn. Voldemort is a pure Dynamo implementation. We discussed its key characteristics and we also talked about some of the problems. In a funny way its biggest problem is rooted in its very cleanness and simplicity.
Let's understand why.