Virtual Domains - vdoms explanation

[Annex31]

Hello,

I'm a student and unfortunately can't afford some of the fortigate devices. But i heard about the vdom feature.

Exactly a friend of mine told me that you can use two hardware devices (60D,90D ...) and put them in a vdom. Then for the clients it look like one single device. The real benefit is if one device crashes the other would do a failover transparently, so no client would see a service interruption.

Does anyone know how Fortinet achieve this functionality. Does anyone know the Technology behind this feature? Is this also possible using Linux and opensource tools? 

Best regards in advance 

Annex