A method is used in managing data placement in storage systems. A portion of an allocated storage space is identified in a data storage system for managing data placement. The allocated storage space includes first and second set of slices. The first set of slices associated with the portion of the allocated storage space in the data storage system is identified. Data of the first set of slices is transferred to the second set of slices of the allocated storage space in the data storage system. The first set of slice is removed from the allocated storage space in the data storage system.