Secutirty of NFS

The nfs-filesystem does not have the reputation of providing a high level of security. So nfs-root systems should not be used in areas where network security is low, or on critical systems altogether (for a Kiosk system it may be well suited though). There are secure solutions for network file-systems, like tunneling nfs or SMB via a VPN, but these do not allow for booting the system in this secure mode (at least not to my knowledge). Also SMB, which is a state-full protocol is clearly better than nfs, but again, I don't know of any bootable setup providing something like smb-root. For systems that might use a local boot-media and then mount applications, or log-partitions over the network both SMB and tunneled NFS are possible with an embedded GNU/Linux system.