A method includes encoding input data into a plurality of slices. The plurality of slices are sent to a first plurality of distributed storage and task execution units for storage, the first plurality of distributed storage and task execution units being located at a corresponding first plurality of sites. Write slice data is received from the first plurality of distributed storage and task execution units. The method determines when replication is to be applied to the plurality of slices. When replication is to be applied to the plurality of slices, a second plurality of distributed storage and task execution units are selected, a plurality of replicated slices corresponding to the plurality of slices are generated, and the plurality of replicated slices are sent to the second plurality of distributed storage and task execution units.