Don’t Settle for Eventual -- Scalable Causal Consistency for Wide-Area Storage with COPS
Will we see a lot COPS clones immediately spring up like we saw when the Dynamo paper was published? I don’t know. Eventually consistent systems like Cassandra get you most of what COP has without the risk. Though COPS has a lot of good features. Causal ordering to a programmer is a beautiful property as are the ALPS properties in general. The emphasis on low-latency is a winner too. Thick client libraries are a minus as they reduce adoption rates. Complex client libraries are very difficult to port to other languages. Not being able to deal with write-write conflicts in an equally programmer friendly manner while maintaining scalability for large systems, is unfortunate, but is just part of the reality of a CAP world. You could say using a strongly consistent model in each datacenter could limit the potential size of your system. But, all together it’s interesting and different. Low-latency, geo-distribution, combined with a more intuitive consistency model could be big drivers for adoption for developers, and it’s developers that matter in these sorts of things.