"The only freely-available tool that attempts to provide both of these is zookeeper, but zookeeper is specialized, focused on locking and server management. We need a general-purpose tool that provides the same guarantees in a clean, well-designed package."
I think they dismissed Zookeeper too quickly without trying to understand it first. The zookeeper primitives (get/set nodes and their children) seems simpler and cleaner than doozer is client protocol, AFAICT. Zookeeper should scale better (especially for readers) than typical Paxos based systems as well.
The problem with zookeeper is there is no safe way to dynamically change the nodes in the cluster. That's where Paxos comes in since it is provably correct even with nodes joining and leaving.
I think they dismissed Zookeeper too quickly without trying to understand it first. The zookeeper primitives (get/set nodes and their children) seems simpler and cleaner than doozer is client protocol, AFAICT. Zookeeper should scale better (especially for readers) than typical Paxos based systems as well.