Handling Large Blobs hard
Dropbox saves petabytes by 'Deduplicating' files. How is this typically implemented?
- A Comparing filenames.
- B Content Addressable Storage (CAS). The file is hashed (SHA-256). The hash becomes the key. If User A and User B upload the same movie, the hash matches, and only one copy is stored.
- C Zipping all files.
- D Manual review.
Answer: B. Content Addressable Storage (CAS). The file is hashed (SHA-256). The hash becomes the key. If User A and User B upload the same movie, the hash matches, and only one copy is stored.
This also enables 'Instant Upload'—if the server already has the hash, it just links the file to your account without transferring bytes.
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