Splitting file
install-us FAQ

"Is it possible to split the installation-files over more disks, when there is not enough space available on one disk?"

Answer: Yes, of course. Go to section "1 - General settings" and click on "Medium". Then select "Disks". In the dialog box "Size" you can specify the number of bytes available on the disks you intend to use. Please note that the file names also take up additional disk space.

Note:
If the available space is not used fully or is not enough on disk number one, you can specify a special value for the size at disk-1: Menu “Installation - Special - Adjust Disk-1-Space”.