1. A method, implemented at least in part by one or more computing devices, for data storage in a collective parallel processing environment, the method comprising: receiving data to be written for a plurality of collective processes within a collective parallel processing environment; before the data is written, extracting a data pattern for the data to be written for the plurality of collective processes; generating a representation describing the data pattern; and saving the data and the representation of the data pattern; wherein the representation is a single index entry, and wherein the representation describing the data pattern comprises information describing: a number of the plurality of collective processes; an offset in files being written when saving the data; a total amount of data being written; and an amount of data being written per collective process.