The entire network is running 10Gb fiber. All RDP hosts are separated by only one switch. The Network isn't saturated by any means. I'm thinking that it's a issue with the storage on the server that's hosting the UPDs. It's a 4-disk raid 10 with WD 7200 RPM Enterprise drives. I just want to make sure the next move I make will take care of this issue and allow me to scale up a bit more as we add more users.

@dbeato are you referring to a quota on the size of the UPD's? I apologise if I'm not understanding what you're referring to. If you are talking about quotas, yes, they're limited to 20GB/ea.

I'm looking for recommendations for User Profile Disks. I currently Have 4 RDS servers (host-based, not VDI) in a farm and have previously implemented User Profile Disks. UPD's worked great all being served up from a standard VM file server, until our user base grew to well over 100 people logging in every morning all at once. What's happening is every morning between 8-9 AM, there are so many people loading up their profiles that everything essentially freezes on all of the RDP hosts until the VM serving UPD's can catch up.

I've been researching best practices for load balancing for our user profile discs and have seen some saying that Scale Out File Server is the way to go. Does anyone have any thoughts or experience in a situation like this? I want to make sure I have this set up in such a way that it can scale further in the future if I need it.