Why does Scalability matter, and how does Cassandra scale?

Scalability refers to the ability to add computational resources to a database for increased throughput. Vertical scalability involves moving to a machine with more capacity, while horizontal scalability allows for incremental addition of hardware. Apache Cassandra is an example of a horizontally scalable system that seamlessly utilizes new resources without reconfiguration or downtime. DataStax Astra DB, built on Cassandra, offers Database-as-a-Service and autoscaling features to save costs and enable global presence.