Zaqar/Feedback

Storage Backends

 * http://voltdb.com/
 * https://foundationdb.com
 * http://www.orientechnologies.com/
 * http://www.rethinkdb.com/

Note: Cassandra has known problems with high data churn, and doesn't solve the issue of atomic marker generation, but if we want to try building workarounds for all that, we can prototype this as a backend as well.