Coupling facility storage is allocated in multiples of the coupling facility model-dependent storage increment size. For coupling facility levels 0 through 14 , all structure allocations are rounded up to a multiple of 256K. At coupling facility level 15, allocations are rounded up to a multiple of 512K. For coupling facility levels 16 and higher, allocations are rounded up to a multiple of 1M. See the "PR/SM Planning Guide" for current storage increment sizes.

Storage-class memory (CFLEVEL 19 and above) is allocated in multiples of the coupling facility model-dependent storage-class memory increment size. The increment size is 1M.