Optimizing rebuilds when using multiple information dispersal algorithms

A dispersed storage integrity processing unit for use in a dispersed storage network, the dispersed storage network including a first set of dispersed storage units storing a first set of encoded data slices and a second set of dispersed storage units storing a second set of encoded data slices, wherein a data segment is dispersed storage error encoded using first dispersal parameters and differing second dispersal parameters to produce, respectively, the first and second sets of encoded data slices, the dispersed storage integrity processing unit comprising:

• a communications interface;
• a memory;
• and
• a computer processor;
• where the memory includes instructions for causing the computer processor to:
• identify a storage error associated with a first encoded data slice of the first set of encoded data slices;
• in response to identifying the storage error, determine that a first decode threshold number associated with the first dispersal parameters is greater than a second decode threshold number associated with the second dispersal parameters;
• obtain, via the communications interface, a second decode threshold number of second encoded data slices of the second set of encoded data slices;
• generate a rebuilt encoded data slice associated with the first encoded data slice using the second decode threshold number of second encoded data slices;
• and
• issue, via the communications interface, a write slice request to store the rebuilt encoded data slice associated with the first encoded data slice.

A dispersed storage network comprising:

• a first set of dispersed storage units storing a first set of encoded data slices, wherein a data segment is dispersed storage error encoded using first dispersal parameters to produce the first set of encoded data slices;
• a second set of dispersed storage units storing a second set of encoded data slices, wherein the data segment is dispersed storage error encoded using second dispersal parameters to produce the second set of encoded data slices;
• and
• a disperse storage integrity processing unit including:
• a communications interface;
• a memory;
• and
• a computer processor;
• where the memory includes instructions for causing the computer processor to:
• identify a storage error associated with a first encoded data slice of the first set of encoded data slices;
• determine that a first decode threshold number associated with the first dispersal parameters is greater than a second decode threshold number associated with the second dispersal parameters;
• obtain, via the communications interface, a second decode threshold number of second encoded data slices of the second set of encoded data slices;
• generate a rebuilt encoded data slice associated with the first encoded data slice using the second decode threshold number of second encoded data slices;
• and
• store the rebuilt encoded data slice associated with the first encoded data slice.