1. A method comprising: maintaining, in a data storage system, a plurality of blocks of data, the storage system representing a plurality of sets of digital data, by associating each of said sets of digital data with at least one of said plurality of blocks; maintaining a first timestamp corresponding to each of the plurality of blocks, the first timestamp indicating a last time when a block was verified to have been associated with at least one of said sets of digital data; maintaining a second timestamp corresponding to each of the sets of digital data, the second timestamp indicating a time when an association between a set of digital data and at least one of said plurality of blocks was verified; providing an indication that a given block that is not associated with any of the sets of digital data is in the process of being removed from the storage system, wherein the first timestamp associated with the block indicates an earlier time than each of the second timestamps; deleting the given block of data from the storage system; and providing an indication that the block has been removed from the storage system.