1. A method of growing a dispersed storage network, the dispersed storage network including a first set of dispersed storage units, wherein a first dispersed storage unit of the first set of dispersed storage units stores a first encoded data slice and a second encoded data slice and wherein the first encoded data slice and the second encoded data slice originate from a first data source, the method comprising: assigning one or more additional dispersed storage units to the dispersed storage network including the first set of dispersed storage units to form a second set of dispersed storage units the second set of dispersed storage units including the first set of dispersed storage units and the one or more additional dispersed storage units; reallocating the first encoded data slice from the first dispersed storage unit to at least one of the one or more additional dispersed storage units of the second set of dispersed storage units that does not presently store the first encoded data slice; and facilitating migration of the first encoded data slice from the first dispersed storage unit to the at least one of the one or more additional dispersed storage units of the second set of dispersed storage units that does not presently store the first encoded data slice.