A method for memory management, the method may include receiving an updated portion of a data unit, the data unit is associated with a logical data entity; wherein the updated portion is smaller than a granularity of a mapping data structure used for retrieval of the data unit; and creating, by the storage system an extended data unit that comprises (i) an original content of the data unit, (ii) the updated portion and, (iii) updated portion metadata; wherein the updated portion metadata comprises (a) updated portion retrieval information for retrieving the updated portion, and (b) updated portion snapshot information indicative of at least one snapshot associated with the updated portion.