Recovering missing data in a storage network via locally decodable redundancy data

Abstract

A processing system of a storage network operates by: sending, to at least one storage unit of the storage network, at least one read request corresponding to at least a read threshold number of a set of encoded data slices to be retrieved, wherein the set of encoded data slices correspond to data, wherein the data is coded in accordance with dispersed error coding parameters that include a write threshold number and the read threshold number, wherein the write threshold number is a number of encoded data slices in the set of encoded data slices and wherein the read threshold number is a number of the set of encoded data slices that is required to decode the data; receiving, at the at least one processing circuit and from the at least one storage unit, a first subset of the set of encoded data slices, wherein at least one missing encoded data slice was not included in the first subset and wherein a number of encoded data slices in the first subset is less than the read threshold number; generating, via the at least one processing circuit, at least one rebuilt encoded data slice corresponding to the at least one missing encoded data slice utilizing locally decodable redundancy data, wherein the locally decodable redundancy data corresponds to a second subset of the set of encoded data slices that includes the at least one missing encoded data slice and wherein the locally decodable redundancy data is stored locally to the processing circuit; and recovering, via the at least one processing circuit, the data based on the at least one rebuilt encoded data slice and the first subset.