The problem is the following: I created an NFS share from OpenFiler, and when I tried to mount it using the NFS client on other server, it mounted successfully, but I couldn’t change ownership of the NFS share, as follows:

[root@egohstest04 ~]# chown -R siebel:siebel /ttslab2/siebel/siebelfs
chown: changing ownership of `/ttslab2/siebel/siebelfs’: Operation not permitted

The solution to this is to edit the NFS share options, and change the UID/GID Mapping to “no_root_squash”, and there you go 🙂

Enjoy!

Source: http://www.linuxquestions.org/questions/linux-server-73/nfs-and-chown-wtf-552879/