A method begins by a processing module receiving an encoded data slice to store and determining a slice length of the encoded data slice. The method continues with the processing module comparing the slice length to a plurality of bin widths, wherein each of the plurality of bin widths represents a fixed storage width of a plurality of memory bins within each of a plurality of memory containers, wherein a storage unit includes the plurality of memory containers. The method continues with the processing module selecting one of the plurality of memory containers based on the comparing to produce a selected memory container, identifying an available bin of the plurality of bins of the selected memory container, and storing the encoded data slice in the available bin.