title: Graph database implemented using key value store
body: <p>I have a requirement for a graph database that needs to be backed-up and potentially accessed at a lower level of abstraction. It is also must be distributed for the sake of load balancing, (single master replication will do).</p>
  
  <p>I know that it is possible to implement a graph database using a self-referencing key-value store. The Git object database is an example of this pattern. One of the frustrating things I find about most graph databases is that they do not "disclose" their underlying persistence layer in public api.</p>
  
  <p>Do any replicated graph databases exist that allow for an underlying key-value stores to be "plugged-in" or accessed directly?</p>