To add external hard disk
Access KVM interface.
In the VM where you want to add an external disk click
icon.
Click Add Hardware.
In the Add New Virtual Hardware screen,
Select Storage.
Select Create a disk image for the virtual machine and assign the required GiB.
Select Bus Type as SCSI.
Click Finish.
Click
icon to launch the CLI console.
In the CLI console type show disks.
Initialize the disk.
Type disk initialize.
Enter the name of the disk to initialize.
Type yes when prompted for confirmation.
Enter a new password when prompted for password.
Activate the disk. Type disk activate. It will reboot the VM and mount the disk on boot. Please enter the password when prompted.
The password is the password that you have configured in step 6 above.
After the VM reboots, the disk will be active.