Expanding information dispersal algorithm width without rebuilding through imposter slices

A dispersed storage processing unit for use in a dispersed storage network, the dispersed storage network including an initial set of dispersed storage units, the dispersed storage processing unit comprising:

• a communications interface;
• a memory;
• and
• a processor;
• wherein the memory includes a set of encoded data slices and wherein the memory further includes instructions for causing the processor to:
• at a first time, store in each respective dispersed storage unit of the initial set of dispersed storage units a respective encoded data slice of the set of encoded data slices;
• at a second time detect an expansion of the initial set of dispersed storage units to include new dispersed storage units, the expansion resulting in an expanded set of dispersed storage units, wherein the expansion of the initial set of dispersed storage units is based on increasing a write threshold;
• identify primary storage units of the expanded set of dispersed storage units;
• and
• for each respective primary storage unit of the expanded set of dispersed storage units that is one of the new dispersed storage units, store the respective encoded data slice of one of the respective dispersed storage units of the initial set of dispersed storage units that is not one of the primary storage units.

A dispersed storage network comprising:

• an initial set of dispersed storage units;
• and
• a dispersed storage processing unit, the dispersed storage processing unit including:
• a first communications interface;
• a first memory;
• and
• a first processor;
• wherein the first memory includes a set of encoded data slices and wherein the first memory further includes instructions for causing the first processor to:
• at a first time, store in each respective dispersed storage unit of the initial set of dispersed storage units a respective encoded data slice of the set of encoded data slices;
• at a second time detect an expansion of the initial set of dispersed storage units to include new dispersed storage units, the expansion resulting in an expanded set of dispersed storage units;
• and
• for each respective primary storage unit of the expanded set of dispersed storage units that is one of the new dispersed storage units, store the respective encoded data slice of one of the respective dispersed storage units of the initial set of dispersed storage units that is not one of the primary storage units;
• wherein one or more of the dispersed storage units of the initial set of dispersed storage units include:
• a second communications interface;
• a second memory;
• and
• a second processor;
• and
• wherein the second memory includes instructions for causing the second processor to identify primary storage units of the expanded set of dispersed storage units based on a write threshold associated with the expanded set of dispersed storage units.