1. 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: identifying a plurality of encoded data slices that require rebuilding, wherein rebuilding of the plurality of encoded data slices is queued for at least one of individual, group, or batch processing and the processing will be performed at a significant time delay from the queuing; determining an amount of memory required for storage of rebuilt encoded data slices for the plurality of encoded data slices; updating utilization information of the memory by allocating a portion of available memory to the amount of memory required; obtaining rebuilt encoded data slices; storing the rebuilt encoded data slices in the reserve memory; and modifying the utilization information to reflect the stored rebuilt encoded data slices.