Which deduplication method is used by inline deduplication devices?

Object differencing is not a recognized inline deduplication method - it is a concept more associated with object storage versioning or differential backup strategies rather than inline dedup processing.

Zone-level is not a standard deduplication method; deduplication operates at the data chunk or block level, not at a zone abstraction.

Byte-level-delta (delta differencing) is a compression technique that records only the differences between data versions, used in post-process or replication deduplication scenarios rather than inline write-path deduplication.

Hash-based chunking divides incoming data into variable or fixed-size segments, computes a cryptographic hash for each chunk, and compares that hash against a stored index to identify duplicates before writing to disk. Because this process occurs inline - in the active write path - no duplicate data is ever physically stored. The hash index enables rapid lookup at wire speed, making hash-based chunking the standard and practical method for inline deduplication appliances.