I haven't used Cassandra for about 3 years, and this is awakening memories. At a previous company I inherited a very badly assembled cluster that was used for a time series database. The guys who built it said (and no, I'm not kidding...) "we don't need to put a TTL on metrics because they're tiny and anyway we can just add more nodes and scale the cluster horizontally forever!". Well, forever was about 2 years, when the physical data center ran out of rack space, and teams abused the metrics system with TBs of bullshit data. That was when they handed the whole metrics system to yours truly. And I discover two things:<p>1. You can't just bulk delete a year of old stale data without breaking it<p>2. "Woops, did we really set replication factor to 1?"<p>Fun.