I'm wondering if they taken a look at BookKeeper[1] for this? It's basically a system on top of ZK to handle replication log in a decentralized way.

[1] https://bookkeeper.apache.org/index.html

Edit: It would be a nice to tell me why my my post have been downvoted. BookKeeeper is not a competing solution, but something that was written for that purpose and they could utilize it.