Apache Cassandra vs Microsoft SQL Server

Apache Cassandra is a free, open-source NoSQL distributed database for mission-critical data and large active datasets. Its masterless architecture gives each node the same functionality. The project says read and write throughput can grow linearly as machines are added, without downtime or application interruption. Cassandra can run on premises, with one cloud provider, across multiple providers, or in a combination of those environments. It supports replication across data centers and configurable consistency levels for queries, along with CQL, transactions, and horizontal scaling. The project lists audit logging for DML, DDL, and DCL activity, and fqltool for recording and replaying production workloads. Drivers are available for Java, Go, Python, and Node.js; downloads include tarballs and packages, and installation guidance covers Debian and RPM. The ecosystem includes tools and connectors for Apache Kafka, Apache Flink, Apache Spark, and Kubernetes. The project identifies version 5.0 as the latest GA release and says it is maintained until the 8.0 release. Cassandra is self-managed, and listed third-party ecosystem projects are not supported by its community.

Microsoft SQL Server is a database platform for storing, processing, and securing data, offered with both deployment models and a free plan. Its Database Engine includes replication, full-text search, relational, XML, and JSON data management, as well as Python and R machine-learning services. Integration Services provides graphical tools and programmable objects for moving and transforming data, while PolyBase can query Azure Storage, S3, and ODBC sources. SQL Server 2025 adds vector search, vector embedding generation, text chunking, and DiskANN vector indexing, and integrates with LangChain, Semantic Kernel, Entity Framework Core, Microsoft Azure, and Microsoft Fabric. Microsoft provides downloads for Windows and Linux and a SQL Server container image for Docker. Express is a free entry-level edition for learning and desktop or small server applications; its single Database Engine instance is limited to the lesser of one socket or four cores. Developer editions provide Enterprise or Standard functionality for development and testing, not production. SQL Server 2025 does not support SUSE Linux Enterprise Server.