# get the disk id because letter names (/dev/sda etc) are volatile
# hint: use lsblk to find the drive you are trying to add
find /dev/disk/by-id/ -type l|xargs -I{} ls -l {}|grep -v -E '[0-9]$' |sort -k11|cut -d' ' -f9,10,11,12
qm set  -scsi /dev/disk/by-id/
# example: qm set 102 -scsi1 /dev/disk/by-id/