ScyllaDB is a C++ rewrite of Apache Cassandra. Same CQL API, same data model, same operational tools — but ~3-10x throughput per node and no JVM. For new Cassandra-style workloads in 2026, Scylla is usually the better starting point.
Performance delta
Per node: Cassandra ~50K ops/sec, Scylla ~500K ops/sec on the same hardware. Latency p99: Cassandra ~50ms, Scylla ~5ms. The difference is thread-per-core architecture (no GC pauses) and a more efficient I/O path.
Operational model
Same nodetool, same JMX-like metrics (actually exposed via REST), same repair/compaction workflow. Migrating Cassandra ops knowledge is near-zero cost. ScyllaDB Manager is the SaaS equivalent of OpsCenter, with similar feel.
Compatibility
ScyllaDB targets CQL 3.x — drop-in for most Cassandra apps. Some advanced features (like specific UDFs) may differ. Migration tool: ScyllaDB Migrator copies data via Spark; or use sstableloader.
Cost
Open-source ScyllaDB is free; ScyllaDB Cloud (managed) starts cheaper than DataStax Astra at scale. Self-hosted Scylla on Kubernetes is straightforward; community support is responsive.
When to stick with Cassandra
Existing massive Cassandra deployment with deep operational tooling investment — migration ROI may not justify rework. Hard dependency on Cassandra-specific features (some triggers, JVM-based UDFs). Otherwise, evaluate Scylla.