A storage system has a plurality of heterogenous storage nodes characterized by non-uniform total non-volatile storage capacity. Storage capacity of all nodes is configured as same-size cells and represented as a set of matrices. The matrices have dimensions corresponding to consecutive cell indices and consecutive storage node indices. Initially, storage nodes having the same storage capacity are consecutively indexed so that the representative matrices are not ragged due to gaps, referred to herein as non-contiguous storage space, where cells do not exist because of differences in numbers of cells in adjacently indexed storage nodes. Addition of more heterogeneous storage nodes can create such gaps when the cells of those storage nodes are added to the matrices. The gaps are managed in the ragged matrix representations by coalescing the non-contiguous storage space, thereby enabling selected protection group members to be relocated using matrix mathematics such as linear algebra so that new protection groups can be created, and capacity can be scaled.