I have deployed and run Cassandra myself, basically as you describe. The first 'dev' Cassandra install was three nodes. I downloaded the .tar.gz, installed it,

I have deployed and run Cassandra myself, basically as you describe. The first 'dev' Cassandra install was three nodes. I downloaded the .tar.gz, installed it, started each process in turn on each node with the required configuration. That was 2012 and there is a chance that cluster is still running. It was low-volume in terms of data. TTL configured so it would never run out of disk. Never had any issues in particular. I used it for ~5 years before concluding work with that client. The problem in that case was Cassandra proliferated in that small company, they didn't build any particular expertise beyond me, and in the end I was being pulled into discussions from different teams, different products, split across about 13 clusters. Wasn't much fun - but that wasn't the DB's fault.