For the first 3 years of Stream we used Cassandra. Afterwards we switched to a custom RocksDB + Raft solution. (somewhat outdated stackshare interview: https://stackshare.io/stream/stream-and-go-news-feeds-for-ov...)

The difference is massive. Cassandra was hard to manage and after many years of our team using it still had random spikes. RocksDB+Raft has been extremely solid, doesn't require any maintenance, load times are flat, zero spikes.

Cassandra was awesome, but it definitely has some issues. That's also why companies like ScyllaDB see space in that market. I wonder if AWS's cassandra implementation is better than regular cassandra.