Coalescing storage space of heterogeneous nodes for flexible expansion

A method implemented with storage nodes sorted as a function of non-volatile storage capacity and the storage nodes assigned contiguous indices as sorted, the non-volatile storage capacity subdivided into indexed same-size cells, and the storage capacity represented as matrices of P contiguously indexed cells and ii) the storage nodes contiguously ordered, the method comprising:

• responsive to creation of at least one gap in one of the matrices from addition of at least one new consecutively indexed storage node having different storage capacity than an adjacently indexed storage node:
• coalescing cells adjacent to the at least one gap;
• and
• relocating selected protection group members, in the cells adjacent to the at least one gap, to cells of the at least one new consecutively index storage node based on the matrices.

A non-transitory computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method with storage nodes sorted as a function of non-volatile storage capacity and the storage nodes assigned contiguous indices as sorted, the non-volatile storage capacity subdivided into indexed same-size cells, and the storage capacity represented as matrices of i) contiguously indexed cells and ii) the storage node contiguously ordered, the method comprising:

• responsive to creation of at least one gap in one of the matrices from addition of at least one new consecutively indexed storage node having different storage capacity than an adjacently indexed storage node:
• coalescing cells adjacent to the at least one gap;
• and
• relocating selected protection group members, in the cells adjacent to the at least one gap, to cells of the at least one new consecutively indexed storage node based on the matrices.