I wanted to share partitions via NFS. I followed: http://gentoo-wiki.com/HOWTO_Share_Directories_via_NFS At first I got the errors:
* Error starting NFS daemon
clientmachinename:/directory/to/export: Function not implemented
The mistake was to skip the kernel compilation step. Simply build modules for NFS server and call modprobe nfsd. You don't even have to restart your machine.