Spent the first few minutes on the obvious stuff, chunking files, metadata storage, sync conflicts.
Start by clarifying functional and non-functional requirements, then sketch a high-level architecture covering client, metadata service, block storage, and sync engine. Dive into critical components like chunking, deduplication, conflict resolution, and consistency models, discussing trade-offs at each step.
Pro tip: Emphasize the delta sync and chunk-level deduplication early, as it's the core of Dropbox's efficiency; also proactively discuss how you'd handle large files and network interruptions to show depth.
Ask about scale (users, files, size), consistency needs, offline support, and security. Define core features: upload, download, sync across devices, versioning, sharing.
Outline components: client apps, load balancers, API servers, metadata database, block storage (e.g., S3), notification service, and sync engine. Explain data flow for upload/download.
Design metadata schema (files, chunks, versions, devices) and block storage layout. Discuss chunking strategy (e.g., 4MB blocks), deduplication via content hashing, and compression/encryption.
Detail how clients detect changes (long polling, WebSocket), delta sync, conflict resolution (last-write-wins, version vectors), and consistency models (eventual vs strong).
Address scaling metadata (sharding, caching), storage (CDN, geo-replication), and trade-offs like consistency vs availability, cost vs performance, and security vs usability.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.