Maximizing redundant information in a mirrored vault

A computing device of a group of computing devices of a dispersed storage network (DSN), the computing device comprises:

• an interface;
• a local memory;
• and
• a processing module operably coupled to the interface and the local memory, wherein the processing module functions to:
• disperse storage error encode data for storage utilizing an encoding matrix to produce a first plurality of sets of encoded data slices;
• when the data is to be mirror stored, disperse storage error encoding the data for storage utilizing a second encoding matrix to produce extension encoded data slices of a second plurality of sets of encoded data slices;
• send, via a network, the first plurality of sets encoded data slices to a first set of storage units;
• send, via the network, the second plurality of sets of encoded data slices to a second set of storage units;
• and
• when retrieving the data, for each set, recover at least a decode threshold number of encoded data slices of either of the first or second plurality of sets of encoded data slices.

A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises:

• dispersed storage error encoding data for storage utilizing an encoding matrix to produce a first plurality of sets of encoded data slices;
• when the data is to be mirror stored, dispersed storage error encoding the data utilizing an extension encoding matrix to produce a plurality of groups of extension encoded data slices;
• sending, via a network, the first plurality of sets of encoded data slices to a first set of storage units;
• sending, via the network, the second plurality of sets of encoded data slices to a second set of storage units;
• and
• when retrieving the data, for each set, recovering at least a decode threshold number of encoded data slices of either of the first or second plurality of sets of encoded data slices.