Eric Day announced SlackDB a few weeks ago, and on his blog yesterday, he answered a lot of the questions people were throwing at him about the new project.
One of the most often asked questions about SlackDB was, “Isn’t this what Drizzle is doing?”
The short answer is “no.”
The long answer is, “They are both being designed for ‘the cloud’ and speak the MySQL protocol, but they provide very different guarantees around consistency and high-availability. The simple answer is that SlackDB will provide true multi-master configurations through a deterministic and idempotent replication model (conflicts will be resolved via timestamps), where Drizzle still maintains transactions and ACID properties, which imply single master. Drizzle could add support for clustered configurations and distributed transactions (like the NDB storage engine), but writes would still happen on the majority (maintain quorum) since the concept of global state needs to be maintained.”