US Patent 10530862 Determining slices to rebuild from low-level failures

A distributed storage network (DSN) includes multiple distributed storage task execution (DST EX) units, each employing multiple memory portions to store encoded data slices. A DST EX unit detects a physical storage failure associated with an affected memory portion of a storage unit included in the DST EX unit. A memory portion identifier of the affected memory portion is used to identify a range of impacted encoded data slices associated with the affected memory portion, and in some cases specific encoded data slices within that range. The DST Ex unit issues rebuilding information to the DSN. The rebuilding information includes at least one identifier associated with at least one impacted encoded data slice included in the range of impacted encoded data slices.