The Rise of Cloud ACID Databases

Cloud Spanner and AWS Aurora among others are promising traditional RDBMS capabilities with cloud scale-out (does not mean cheaper btw).

Here is interesting article comparing Cloud Spanner with its inspired open source offshoot called CockroachDB.

The somewhat established, niche SQL scale-out contenders, like Clustrix, MemSQL VoltDB and NuoDB are getting more competition than they can handle these days from all sides.