Addding Harddisk to VirtualBox

1. Select your vbox image that you want to add additional harddisk. Left click -> Settings -> Storage -> Add Hard Disk -> Create new disk -> VDI -> Dynamically allocated -> Select location and size
2. Launch your virtualbox system
3. ls /dev/sd* (the one without numbers is the new disk)
4. su -
5. fdisk /dev/sdb (depending on where your hdd is mounted)
6. Enter c then u.
7. Enter p
8. Select your partition number
9. Enter the sectors needed
10. Enter w to write the changes
11. ls /dev/sd* ( Your new harddisk will show up with number, i.e. sda1, sdb1, etc
12. mkdir /backup
13. mkfs.ext4 -L /backup /dev/sdb1
14. mount /dev/sdb1 /backup
15. mount ( look for your new drive)
16. Add LABEL=/backup /backup ext4 defaults 1 2 to your /etc/fstab
17. Reboot
18. cd / (You should notice backup folder is created. Your new hard disk is mounted to it.
19. You can start using the new drive.