Focused storage pool expansion to prevent a performance degradation

A computing device comprising:

• an interface configured to interface and communicate with a dispersed storage network (DSN);
• memory that stores operational instructions;
• and
• a processing module operably coupled to the interface and to the memory, wherein the processing module, when operable within the computing device based on the operational instructions, is configured to:
• based on a change from a first system configuration of a Decentralized, or Distributed, Agreement Protocol (DAP) to a second system configuration of the DAP that is based on addition or removal of at least one storage unit (SU) within a plurality of storage units (SUs) within the DSN, wherein the first system configuration of the DAP and the second system configuration of the DAP respectively provide for deterministic calculation of locations of encoded data slice (EDS) sets that correspond respectively to a plurality of data segments of a data object that are distributedly stored across the plurality of storage units SUs within the DSN:
• direct, via the interface and via the DSN, the plurality of SUs to update from the first system configuration of the DAP to the second system configuration of the DAP including permitting a limited number of the plurality of SUs to perform simultaneous update from the first system configuration of the DAP to the second system configuration of the DAP that ensures servicing of at least one of read or write requests to the plurality of SUs during updating from the first system configuration of the DAP to the second system configuration of the DAP;
• direct, via the interface and via the DSN, the plurality of SUs to operate based on the first system configuration of the DAP when fewer than a number of SUs of the plurality of SUs that facilitates the servicing of the at least one of the read or the write requests to the plurality of SUs have successfully updated from the first system configuration of the DAP to the second system configuration of the DAP;
• and
• direct, via the interface and via the DSN, the plurality of SUs to operate based on the second system configuration of the DAP after the number of SUs of the plurality of SUs that facilitates the servicing of the at least one of the read or the write requests to the plurality of SUs have successfully updated from the first system configuration of the DAP to the second system configuration of the DAP.