A method and a data based bookmark management system for data based bookmark management in a storage unit are provided. The method includes performing an analysis of a plurality of bookmarks assigned in at least one logical unit number (LUN) of the storage unit to identify at least one bookmark having an expiration time that has been reached; deleting the identified at least one bookmark; determining that data referred by the deleted bookmark is not referred by at least another bookmark of the plurality of bookmarks having an expiration time that has not been reached; and removing from the storage unit the data respective of the deleted at least one bookmark, upon determination that the data is not referred to by the at least another bookmark.