I am considering running ROON Server on a NUC so naturally ROCK sounds like a great way to do this.
Currently all my music sits on my NAS accessible outside of the NAS via an NFS share.
I have a Plex server (running on Ubuntu) and it access this NFS share through a mnt.
Can i do the same thing on my ROCK? point it at my music library on my NAS NFS shared folder?
Or can i only point ROCK at an SMB share?
If that is what you need, then run Linux and the Linux RoonServer. The Roonserver installed on Rock is the same one.
If you are looking for a quick and easy Linux distro, then try Diet Pi for PC. After install, you get a menu to install further software, including RoonServer and Roon Extension Manager (which cannot be run on ROCK).
I’m a bit confused. ROCK needs an NFS client for this, not server. Is that also not supported?
i dont need an NFS server. i need to mnt to an NFS share that is on my NAS. so ROCK is the client, consuming the share.
correct, i need the ROCK to mnt to an existing NFS share on my NAS. it doesn’t need to serve the NFS share.
If you go to the ROCK FAQ you’ll see this line under Other important notes on hardware support:.
ROCK can also mount SMB shares (but not AFP or NFS)
Perhaps ROCK is stripped down a bit too much. Or perhaps Windows is more important than Linux 
It would be a bit strange if it could connect to NFS but the ROCK storage was only accessible by SMB, I suppose