Milvus

What is Milvus?

FAISS is a library — you build the service and manage memory yourself. Milvus is a database: an open-source database built specifically for vectors. You store vectors, build indexes and query them like a normal database, while it handles the production-grade headaches for you: distributed scaling, persistence and the rest.

How is it different from FAISS?

FAISS: a search library
Lower-level — it gives you indexes and algorithms, but you handle serving, persistence and scaling yourself. Good for embedding in your own system.
Milvus: a full vector database
Ships with storage, indexing, a query interface, replicas and horizontal scaling, ready out of the box as a standalone service.

What are its core capabilities?

Multiple index types
Built-in IVF, HNSW, PQ and other approximate nearest-neighbor indexes, so you can trade speed against accuracy.
Hybrid queries
Find "the most similar" by vector and add scalar filters on top — like "most similar products under $100".
Horizontal scaling
Add nodes to scale out when data or concurrency grows, supporting billions of vectors.
Persistence and consistency
Data is written to disk and recoverable, and you can tune consistency levels — more peace of mind in production.

Where does it fit?

Any production system where vectors are the core: RAG Q&A, recommendation, image search, semantic search, deduplication and risk control. In short, you use it instead of hand-rolling a FAISS-based service, so you can focus on your product.

Bottom line: Milvus is a database for vectors — it stores billions of them, queries fast, scales out, and is a common foundation for production RAG.