System design interview question
"Design Dropbox. A folder on my laptop syncs to the cloud and to my other devices. Edits propagate in seconds, it works offline, and it handles a 2 GB file where I changed one paragraph. 500 million users."
efficient differential sync plus conflict resolution across devices. The distinguishing content is chunking and deduplication — the whole reason Dropbox is a hard problem is that re-uploading a 2 GB file because one byte changed is unacceptable. Candidates who design "upload the file to S3" have missed it entirely.
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