method 1
ls/sys/class/scsi_host/
echo"_ _ _ " > /sys/class/scsi_host/host/host0/scan
echo"_ _ _ " > /sys/class/scsi_host/host/host1/scan
echo"_ _ _ " > /sys/class/scsi_host/host/host2/scan
fdisk -l to see if adding on
Method 2
cat / proc / scsi / scsi # view the device ID, the biggest plus 1 ID, every time you add a hard drive
echo "scsi add-single-device 0 0 4 0" > /proc/scsi/scsi
echo "scsi add-single-device 0 0 5 0" > /proc/scsi/scsi
fdisk -l to see if adding on