US Patent 7814149 Client side data deduplication

Methods and systems that use a client locality table when performing client-side data deduplication are disclosed. One method involves searching one or more client locality tables for the signature of a data unit (e.g., a portion of a volume or file). The client locality tables include signatures of data units stored in a deduplicated data store. If the signature is not found in the client locality tables, the signature is sent from a deduplication client to a deduplication server and added to one of the client locality tables. If instead the signature is found in the client locality tables, sending of the new signature to the deduplication server is inhibited.