Can't talk about current employer, but precious employer ran thousands of Cassandra nodes to capture and index billions of events a day into a real time graph.

Can't talk about current employer, but precious employer ran thousands of Cassandra nodes to capture and index billions of events a day into a real time graph. Talking petabytes of data, millions of writes per second, in order to fight hackers. Doing that with an RDBMS would be ... unpleasant. Doing it with Cassandra isn't trivial, but it's straightforward, cross-cloud capable, cross-DC HA, linear scaling, and tunable consistency. Data integrity is a nonissue - when you're dealing with the scale nosql was meant to solve, you're probably smart enough to learn how to write multiple places safely.