ScyllaDB

ScyllaDB is a distributed, open-source NoSQL database designed as a drop-in replacement for Apache Cassandra. It aims to deliver high throughput and low latency at scale by re-architecting Cassandra’s data path in a modern language and runtime.

Written in C++ and built on the Seastar framework, Scylla uses a shard-per-core design that provides per-core task execution and aims to minimize garbage collection pauses and context switches common in JVM-based systems.

The database preserves Cassandra’s data model and query interface through the Cassandra Query Language (CQL) and the native protocol, allowing applications and drivers written for Cassandra to connect with little or no changes.

Data is partitioned and distributed across the cluster with a consistent hashing ring. Each node handles multiple shards, mapped to CPU cores for concurrency.

Scylla provides automatic sharding, online scaling by adding nodes, and multi-datacenter replication with tunable consistency levels, making it suitable for real-time analytics, time-series, and high-traffic workloads.

Management and tooling: Scylla Manager for cluster lifecycle and maintenance, Scylla Cloud for a managed service, and monitoring via Prometheus/Grafana; supports security features such as encryption in transit and Cassandra-compatible authentication.

The project is developed as open-source with commercial offerings and active community.