Pessimistic data reading in a dispersed storage network

摘要

A method begins by a processing module receiving a data retrieval request and determining a read threshold number of dispersed storage (DS). The method continues with the processing module sending read request messages to DS units and receiving encoded data slices to produce received encoded data slices. The method continues with the processing module determining an incremental number of encoded data slices based on the number of received encoded data slices, determining an incremental number of DS units, and sending a read request message to each of the incremental number of DS units when the number of received encoded data slices compares unfavorably to a decode threshold number. The method continues with the processing module dispersed storage error decoding the received encoded data slices to produce data when the number of received encoded data slices compares favorably to the decode threshold number of encoded data slices.

主权项

1. A method comprises:
receiving a data retrieval request; determining a read threshold number of encoded data slices in response to the data retrieval request; sending read request messages regarding the read threshold number of encoded data slices to storage units of a dispersed storage network; entering a loop, wherein the loop includes:
receiving encoded data slices of the read threshold number of encoded data slices within a time period to produce received encoded data slices;when a number of received encoded data slices compares unfavorably to a decode threshold number:
determining an incremental number of encoded data slices based on the number of received encoded data slices and the decode threshold number;sending a read request message regarding the incremental number of encoded data slices to other storage units of the dispersed storage network; andrepeating the loop; andwhen the number of received encoded data slices compares favorably to the decode threshold number of encoded data slices, exiting the loop; and dispersed storage error decoding the received encoded data slices to recapture a data segment of data.