I am running it on a debian VPS with 6 GB and 4 Proc.
Memory seems to be the more critical ressource, because when I used it before with just 2 GB, it didn't really work.
Disk depends on the required storage but should be some 4 GB for installation an some data to play around.
There are somewhere some hintes to size the systam from the data side (just google)
This is just info from my installation.
