I had a real Linux server system that I need to convert into virtual server, because I wanted to sell my old hardware, but I needed the system as backup. This backup is able to run as virtual server. This is a very useful backup method. This tutorial show you how you can convert your whole system into virtualbox system. Virtualbox is a free opensource virtual computer solution from Oracle.
1. Backup your system disk
If you can, put your system disk to another computer. But if you can't do it you can do it the original system.