So far I have seen an article on performance and scalability mainly focusing on how long it takes to add new links. But is there any information about limitations regarding number of files, number of folders, total size, etc?

Right now I have a single file server with millions of JPGs (approx 45 TB worth) that are shared on the network through several standard file shares. I plan to create a DFS namespace and replicate all these images to another server for high availability purposes. Will I encounter extra problems with DFS that I'm otherwise not experiencing with plain-jane file shares? Is there a more recommended way to replicate these millions of files and make them available on the network?

EDIT:

I would experiment on my own and write a blog post about it, but I don't have the hardware for the second server yet. I'd like to collect information before buying 45 TB of hard drive space...