System design interview question
Design a Distributed Multi-Region Blob Storage and Object Versioning System (Like S3 at Enterprise Scale)
Design a globally distributed object storage system that handles 500M daily active users, 100 billion object operations per day (70% reads, 30% writes), with objects ranging from kilobytes to multi-gigabytes, and geographic distribution across 6 continents. The system must support strong consistency for metadata, eventual consistency for object data, object versioning with lifecycle policies, distributed garbage collection, and automatic failover between regions with sub-second latency. Key constraints include: minimizing cross-region bandwidth costs, handling 50 million concurrent connections, supporting atomic transactions on metadata operations, and maintaining 99.99% availability while ensuring data durability across multiple independent data centers.
Practice this question step by step with an AI interviewer that reviews your requirements, your architecture and your trade-offs, and scores the design.