## System Design Prompt Design a simplified cloud object storage service (similar to an object store) that allows users to upload and download files. The key focus is **reducing cost by avoiding storing duplicate files** (deduplication). ### Core Requirements - Upload a file (binary blob) and store it durably. - Download a previously uploaded file by an identifier. - Support basic metadata (filename, content-type, size, upload time, owner). - Avoid saving duplicates: if multiple users upload the exact same content, store it only once. ### Non-Goals (to keep it simpler) - No complex lifecycle rules, tiering, or CDN features required. - Permissions can be simplified (assume authenticated users, simple ACL). ### Scale / Assumptions (you may choose reasonable numbers) - Large number of objects; objects can be large (up to multiple GB). - High read/write throughput. - Must be resilient to failures. ### What to Cover - APIs - High-level architecture - Data model and storage layout - Deduplication approach (how to detect duplicates, how to reference shared content) - Consistency and correctness concerns (races, partial uploads) - Deletion / garbage collection (when shared content can be removed) - Operational considerations (monitoring, cost trade-offs)