I liked the video on DFS but I was unsure if DFS will also replicate the security permissions on the folder or subfolder?
Does DFS also replicate security permissions?
If you are asking what I think you're asking. Yes, sort of.
What it does really is separate them and treat the server nodes as an extension of a namespace, so the node becomes an identical copy of each other. If one node fails, you simply replace it and join it and everything in the namespace is replicated to an identical root folder / share with that name.
That's probably a somewhat simplistic view but you wouldn't for example lose your permission because the primary node failed, as long as you keep up with your replication and make sure it hasn't failed to replicate something across to one of the 'partners'.