Counters in Cassandra seem to have been politically driven (something about the design being influenced by Twitter), and given the fact that Cassandra values av

Counters in Cassandra seem to have been politically driven (something about the design being influenced by Twitter), and given the fact that Cassandra values availability over all us, best effort counters at best. So you can't trust them to be 100% accurate (or so I've heard). This is another case of "to run Cassandra you really have to know Cassandra" as Cassandra counters provide a different set of guarantees than Redis (which is single instance) and Mongo (which chooses consistency).