Just self memo. How to attach new SCSI disk without reboot (debian):

    # check what hosts do you have
    ls /sys/class/scsi_host
    host0 host1 host2 host3

    # change 'host0' to 'host1' or any next number that you need
    echo "- - -" > /sys/class/scsi_host/host0/scan

and done

    fdisk -l

Marek Wywiał

and done