Yeah, sorry for missing Redisgraph.

The entire graph is stored in memory and only spans one server. I personally am not sure what happens when that server goes down. How many minutes worth of data is lost? What's the replication strategy for another server to take over the traffic? And what about transactions and correctness?

Those things matter a lot to Dgraph users who are storing and serving their source of truths. Horizontal scalability, persistence, correctness and avoiding downtime with consistent replication have been cornerstones for the design of Dgraph.