Cloud data storage systems, methods, and techniques partition system data symbols into predefined-sized groups and then encode each group to form corresponding parity symbols, encode all data symbols into global redundant symbols, and store each symbol in different failure domains in a manner that ensures independence of failures. In one embodiment, the apparatus can include several apertures in the upper surface of the platen that are coupled to a vacuum source. The iterators include fixed state information that remains constant over a life of the iterator, and further include dynamic state information that is updated over the life of the iterator.