Apache Cassandra
What it is: Distributed NoSQL database designed for massive scale. Wide-column store with no single point of failure, linear scalability.
What It Does Best
Always-on availability. Multi-datacenter replication. Node failures don't cause downtime.
Linear scalability. Add nodes, get proportional performance. No sharding complexity.
Write performance. Optimized for high-velocity writes. Time-series data, IoT sensors, event logs.
Pricing
Free. Open source, Apache 2.0 license. Managed options: DataStax Astra (pay per usage), AWS Keyspaces.
When to Use It
✅ Multi-datacenter deployments
✅ High write throughput requirements
✅ Time-series or IoT data at scale
✅ Need 99.99%+ availability
When NOT to Use It
❌ Complex joins and aggregations (limited query flexibility)
❌ Strong consistency requirements (eventual consistency model)
❌ Small datasets (operational overhead not worth it)
Bottom line: Built for scale and availability. If you need multi-datacenter writes, massive throughput, and can't afford downtime, Cassandra delivers. Learn CQL query patterns before committing.