1. A method comprising: generating a locality table, wherein the generating the locality table comprises sub-dividing a list of signatures into multiple groups of signatures, the locality table comprises a first group of signatures of the multiple groups of signatures, and the list of signatures is stored on a persistent storage device; caching the locality table in memory, wherein each signature of the first group of signatures identifies a respective data unit of a plurality of data units that were consecutively added to a deduplicated data store on the persistent storage device; searching the locality table for a new signature of a new data unit, wherein the new signature is used to determine whether a copy of the new data unit is already present in the deduplicated data store; accessing a pointer table, if the new signature is not found in the locality table, wherein the pointer table stores information indicating a set of the list of signatures stored on the persistent storage device; and searching the set of the list of signatures for the new signature, in response to the accessing the pointer table.