Cassandra consistency levels are a tricky concept, until you familiarise with them. They're based on a simple consideration: not all data and not all queries require the same level of correctness.
Choose the best balance between speed and consistency by setting proper consistency levels.
Cassandra 4.0 GA was released on 26th July 2021. Older versions users need to upgrade quickly.
Cassandra login fails with: "Cannot achieve consistency level LOCAL_ONE"? Let's see why it happens, and how to solve the problem