Calculate the size of part of "splitted" disk in sectors.
PRL_RESULT PrlDisk_CalcSplitPartSize( PRL_UINT64 sizeMib, PRL_UINT64 logicSectorSize, PRL_UINT64_PTR Size );
PrlDisk.h
Part size is X Mb - 100 Mb for "may be smth. happens". Depends of the block size. The result is aligned to block size.