A method and computing device for use in a dispersed storage network (DSN) to recover corrupt encoded data slices. In response to a request to storage units of the DSN for encoded data slices corresponding to a data segment, the computing device of a receives at least a decode threshold number of encoded data slices and at least one integrity error message that provides an indication of a corrupt encoded data slice, such that less than a decoded threshold number of valid slices is received. Utilizing at least one correction approach involving stored integrity data, the computing device then corrects the corrupt slice(s) to produce a decode threshold number of encoded data slices in order to decode the corresponding data segment. A variety of correction approaches may be employed, including a multi-stage approach that utilizes data from both valid and invalid slices.

A processing module issues a distributed agreement protocol (DAP) information to DSN storage units. The method continues with the processing module initiating, by each storage unit of a first set of the plurality of storage units, transfer of locally stored data slices to another storage unit of another set of the plurality of storage units. The method continues with the processing module, while transferring the locally stored data slices, a storage unit receiving an access request for a data slice that has been transferred, obtains the data slice by proxy from the another storage unit. The method continues with the processing module, when completing the transfer of the locally stored data slices, issuing, by each of the storage units, a DAP status to the transition coordinator and, when receiving a conformation of completion of transferring data slices by all of the storage units issuing updated DAP information.

A processing module issues a distributed agreement protocol (DAP) information to DSN storage units. The method continues with the processing module initiating, by each storage unit of a first set of the plurality of storage units, transfer of locally stored data slices to another storage unit of another set of the plurality of storage units. The method continues with the processing module, while transferring the locally stored data slices, a storage unit receiving an access request for a data slice that has been transferred, obtains the data slice by proxy from the another storage unit. The method continues with the processing module, when completing the transfer of the locally stored data slices, issuing, by each of the storage units, a DAP status to the transition coordinator and, when receiving a conformation of completion of transferring data slices by all of the storage units issuing updated DAP information.

A system includes a plurality of functional rating modules configured to execute a deterministic function, a normalizing function and a scoring function using a set of storage unit coefficients that are different for each of the functional rating modules. The functional rating modules are configured to receive an encoded data slice identifier, perform the deterministic function using the encoded data slice identifier and a first storage unit coefficient to produce an interim result, perform the normalization function using interim result to produce a normalized interim result, and perform the scoring function by performing a mathematical function on the normalized interim result to produce a score. The system also includes a ranking module configured to receive the score from each of the plurality of functional rating modules to produce a highest ranked set of storage units for storing a plurality of sets of encoded data slices.

A system includes a plurality of functional rating modules configured to execute a deterministic function, a normalizing function and a scoring function using a set of storage unit coefficients that are different for each of the functional rating modules. The functional rating modules are configured to receive an encoded data slice identifier, perform the deterministic function using the encoded data slice identifier and a first storage unit coefficient to produce an interim result, perform the normalization function using interim result to produce a normalized interim result, and perform the scoring function by performing a mathematical function on the normalized interim result to produce a score. The system also includes a ranking module configured to receive the score from each of the plurality of functional rating modules to produce a highest ranked set of storage units for storing a plurality of sets of encoded data slices.

A method includes identifying a set of the resources that are affiliated with a range of slice names identified by a listing request. The method further includes creating an ordered classification of the set of resources based on the system configuration change and sending the listing request to resources of the set of resources that are in a first class of the ordered classification. The method further includes processing, by the resources in the first class, the listing request to generate a first listing responses and sending the listing request and the first listing responses to second resources of a second class of the ordered classification. The method further includes processing, by the second resources in the second class, the listing request to generate second listing responses. The method further includes generating, by the second resources, cumulated listing responses based on the first and second listing responses.

A method includes identifying a set of the resources that are affiliated with a range of slice names identified by a listing request. The method further includes creating an ordered classification of the set of resources based on the system configuration change and sending the listing request to resources of the set of resources that are in a first class of the ordered classification. The method further includes processing, by the resources in the first class, the listing request to generate a first listing responses and sending the listing request and the first listing responses to second resources of a second class of the ordered classification. The method further includes processing, by the second resources in the second class, the listing request to generate second listing responses. The method further includes generating, by the second resources, cumulated listing responses based on the first and second listing responses.

A method includes identifying resources that are affiliated with a range of slice names of a listing request. The method further includes creating an ordered classification of the resources. The method further includes a resource determining whether it is in a last class of the ordered classification. When the resource is in the last class, it processes the listing request to generate a listing response and sends the listing response to another resource in a next lower class. When the resource is not in the last class, it identifies a second resource for proxying of the listing request and sends the listing request to the second resource. The method further includes receiving a cumulated listing response from the second resource. The method further includes processing the listing request to generate the listing response. The method further includes combining the listing response with the cumulated listing response.

A method includes identifying resources that are affiliated with a range of slice names of a listing request. The method further includes creating an ordered classification of the resources. The method further includes a resource determining whether it is in a last class of the ordered classification. When the resource is in the last class, it processes the listing request to generate a listing response and sends the listing response to another resource in a next lower class. When the resource is not in the last class, it identifies a second resource for proxying of the listing request and sends the listing request to the second resource. The method further includes receiving a cumulated listing response from the second resource. The method further includes processing the listing request to generate the listing response. The method further includes combining the listing response with the cumulated listing response.

A method generates, from an input data stream, multiple lanes of a physical coding sublayer (PCS) signal. The method converts the data stream to a sequence of bit blocks, and periodically inserts into the sequence of bit blocks an alignment marker (AM) group including multiple individual alignment markers for respective ones of the multiple lanes. The method adds security protection to each bit block according to a security protocol to produce a sequence of protected bit blocks, and modifies each AM group with security information to be used by the security protocol to remove the security protection added to the sequence of protected bit blocks. The method applies forward error correction to the sequence of protected bit blocks and the modified AM groups to produce forward error correction codewords, and produces the multiple lanes from the codewords. The method transmits the multiple lanes over an optical link.