[PVE-User] proxmox zfs mirror installation question

[Nils Privat]

Hello,
i want to install proxmox 5 on two ssds on a mirror. I got some older
corsair ssds, one 60gb and one 80gb. The proxmox installer dont let me
install zfs on a mirror because the ssds are not the same size. how
can i tell proxmox that the mirror should be created with the smallest
size of that array... so that the 20gb are just none used space for
overprovising on the 80gb ssd. Must i create a 60gb partition on the
80gb first to install? I dont know if that is right because the
install script probably creates severeal own partitions for
booting/efi etc?!? Thanks for any help and suggestions.
Would be great if the installer detects automatically the smallest
size in the array and use that as hdsize and leave the space upon just
free.

thanks