Vector Databases
Comparing managed Milvus service with in-memory vector search in 2025 — 10 min read
A quick look at which tool fits your needs best
Choose Zilliz Cloud if you need:
Choose Redis if you need:
Zilliz Inc.
Redis Inc.
Built on Milvus with cloud-native enhancements. Separates compute and storage for scalability.
Key Insight: Zilliz Cloud prioritizes scale and persistence over raw speed.
Everything in RAM for maximum performance. RediSearch module adds vector capabilities.
Key Insight: Redis trades persistence and scale for unmatched speed.
Note: Redis performance assumes all data fits in memory. Performance degrades significantly when using disk-based persistence.
Zilliz Cloud
Unlimited scale with persistent storage. Performance consistent regardless of dataset size.
Redis
Limited by available RAM. Exceptional performance for datasets that fit in memory.
Zilliz Cloud
GPU option provides 3-5x performance boost for similarity search workloads.
Redis
No GPU support. Already optimized for CPU-based in-memory operations.
| Dataset Size | Zilliz Cloud | Redis |
|---|---|---|
| 100K vectors | $65/month | $40/month |
| 1M vectors | $65/month | $100/month (8GB) |
| 10M vectors | $240/month | $800/month (64GB) |
| 100M vectors | $800/month | Not practical |
| Cost Efficiency | Better at scale | Better for small data |
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Photo platform needs:
Zilliz's scale essential
Enterprise requirements:
Zilliz's features crucial
E-commerce needs:
Redis speed unmatched
Real-time gaming:
Redis latency critical
Many teams use both databases together for optimal performance:
💡 Implementation Pattern: Use Redis for the top 10% most accessed vectors (hot cache) and Zilliz Cloud for the complete dataset. This provides sub-millisecond latency for common queries while maintaining unlimited scale.
| Requirement | Best Choice | Reasoning |
|---|---|---|
| Sub-millisecond latency | Redis | In-memory performance |
| 100M+ vectors | Zilliz Cloud | Unlimited scale |
| GPU acceleration needed | Zilliz Cloud | GPU support available |
| Cache + vectors | Redis | Unified system |
| Complex filtering | Zilliz Cloud | Advanced capabilities |
| Cost-sensitive at scale | Zilliz Cloud | Better economics |
Zilliz Cloud excels as a persistent, scalable vector database that can handle datasets of any size. Its GPU support, advanced filtering, and managed operations make it ideal for production workloads where scale and features matter more than microsecond latency.
Bottom Line: Choose Zilliz Cloud for large-scale persistent vector search with advanced features.
Redis Vector Search delivers unmatched performance for datasets that fit in memory. Its sub-millisecond latency and ability to combine caching with vector search make it perfect for real-time applications with moderate data sizes.
Bottom Line: Choose Redis when sub-millisecond latency is critical and data fits in memory.
For most production vector search workloads, Zilliz Cloud's scalability and features make it the better choice. However, if your dataset fits in memory and you need sub-millisecond latency, Redis is unbeatable. Consider using both in a hybrid architecture for optimal results.
Our team can help you evaluate options and build the optimal solution for your needs.
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