A method of storing data is disclosed. A set of data blocks, including a plurality of proper subsets of data blocks, is stored. A plurality of first-level parity blocks is generated, wherein each first-level parity block is generated from a corresponding proper subset of data blocks within the plurality of proper subsets of data blocks without reference to other data blocks not in the corresponding proper subset. A second-level parity block is generated, wherein the second level parity block is generated from a plurality of data blocks included in at least two of the plurality of proper subsets of data blocks, and wherein recovery of a lost block in a given proper subset of data blocks is possible without reference to any data blocks not in the given proper subset.