John: I am currently adapting the WAL to append to a cloned copy in HDFS while still being performant.
I think collaborating would be a great idea. I'll work on getting design document together. I will be at the meetup, so we can discuss there the various tasks to work on for this. I see there being quite a bit.
For the questions you asked.
1) To begin with I was thinking about maybe doing just select tables so that you did not have complete replicas. Then maybe working on a way to possibly do total replicas.
2) I am still working out a good way to have ZooKeeper send the updates for the user information. I am not sure about the table metadata yet, as if all we are doing is calling the client API, I think that might be taken care of, shouldn't it? As the slave table will maintain its own metadata.
3) What you described with cloning the table, copying the data, and replicating the logs was my current plan.
4) I have not looked into FATE that much, but will check it out.
5) I am not sure about replicating the splits unless the user defined the splits before hand.
Let me check into FATE, but from the skimming it seems really useful for this.