Interesting. I'm working on an auction platform, and I created something called Atomic Store [1] to enforce consistency in an Akka-based append-only log deployed on a cluster. But it relies on the logs being singletons. I suppose another way to do it would be to have the logs not be singletons, but have them use two-phase commit, or something similar, to keep the whole thing synchronized.

[1] https://github.com/artsy/atomic-store