@AWesterinen I suppose the concern would be if a machine were taken out of rotation for maintenance, but in the mean time there were lots of updates, can Zookeeper reliably store all the updates? Again, if I u/d RDF-Delta correctly, it's journaling all the updates so that a machine can replay that journal on demand. That journal needs to be stored in a HA and durable way.

If I understand it correctly, RDF-Delta itself requires a replicable store for HA?

I wouldn't discount this project just yet as Merck may have decided to move away from rdf altogether. It is a bit of a commitment and for profit companies need to juggle costs. I also say that bc I have been able to get it to compile against fairly recent libs and prelim play looks promising. Functionally, there's quite a bit there that I think would be useful here (bulk load, bulk export, updates, etc all through mapreduce). Will be several weeks before I can pass more judgement but have seen enough to say let's keep this door open and encourage more eyes on it.

That's a bit disappointing b/c it does look like it can scale and has been run through some paces. https://www.linkedin.com/pulse/halyard-tipstricks-trillion-statements-challenge-adam-sotona/

Doesn't Halyard implement this approach already?