Overcoming bottlenecks in partial and traditional rebuild operations

A storage unit (SU) comprising:

• an interface configured to interface and communicate with a dispersed or distributed storage network (DSN);
• memory that stores operational instructions;
• and
• processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to:
• determine to rebuild an encoded data slice (EDS) of a set of encoded data slices (EDSs) based on a storage error of the EDS, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce the set of EDSs, wherein a decode threshold number of EDSs of the set of EDSs are needed to recover the data segment;
• select combining units based on a number of combining units to perform receiving of slice representations to enable rebuilding of the EDS and also based on at least one of storage unit (SU) availability, local network available capacity, wide area network (WAN) available capacity, or system configuration of the DSN;
• facilitate receiving, by the combining units and by the SU, the slice representations of the decode threshold number of EDSs of the set of EDSs, wherein a representation of an EDS of the decode threshold number of EDSs of the set of EDSs includes the EDS of the set of EDSs or a corresponding partially decoded EDS based on the EDS of the set of EDSs based on the storage error of the EDS;
• receive, from a combining unit of the combining units, a combined partial slice that is generated by the combining unit of the combining units based on at least some of the representations of the decode threshold number of EDSs of the set of EDSs received by the combining unit of the combining units from a plurality of other SUs;
• and
• combine the combined partial slice and any additional representation of the decode threshold number of EDSs of the set of EDSs to generate a rebuilt EDS.

A method for execution by a storage unit (SU), the method comprising:

• determining to rebuild an encoded data slice (EDS) of a set of encoded data slices (EDSs) based on a storage error of the EDS, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce the set of EDSs, wherein a decode threshold number of EDSs of the set of EDSs are needed to recover the data segment;
• selecting combining units based on a number of combining units to perform receiving of slice representations to enable rebuilding of the EDS;
• facilitate receiving, by the combining units and by the SU, the slice representations of the decode threshold number of EDSs of the set of EDSs;
• receiving, via an interface of the SU that is configured to interface and communicate with a dispersed or distributed storage network (DSN) and from a combining unit of the combining units, a combined partial slice that is generated by the combining unit of the combining units based on at least some of the representations of the decode threshold number of EDSs of the set of EDSs received by the combining unit of the combining units from a plurality of other SUs;
• and
• combining the combined partial slice and any additional representation of the decode threshold number of EDSs of the set of EDSs to generate a rebuilt EDS.