$ /etc/init.d/nfs-kernel-server start
Exporting directories for NFS kernel daemon....
Starting NFS kernel daemon: nfsdrpc.nfsd: Setting version failed: errno 16 (Device or resource busy)
rpc.nfsd: writing fd to kernel failed: errno 13 (Permission denied)
rpc.nfsd: unable to set any sockets for nfsd
 failed!