NFS Sharing

See How to mount on Linux, Raw devices
Concepts
UID and GID must be the same
 
Activate NFS server on Red Hat Linux
click  to: System Settings - Server Settings - Services
Be sure to start (and save config when done):
    -nfs
or 
chkconfig --list nfs 
    nfs             0:off   1:off   2:off   3:off   4:off   5:off   6:off
chkconfig --level 345 nfs on
chkconfig --list nfs 
    nfs             0:off   1:off   2:off   3:on    4:on    5:on    6:off
service nfs start
Share an NFS folder
click to: System Settings - Server Settings - NFS Server
click Add
    Directory: Select your directory...
    Allow all hosts to access
    Host(s): *

Mount an NFS
create a mount point
    mkdir /mnt/nfsora
mount <ServerHost>:/nfsora /mnt/nfsora

Parameters and tuning
rsize and wsize default to 1024, that may be increased to 8192 if the system supports it

[/etc/fstab]
# device             mountpoint fs-type    options              dump fsckorder
...
eris:/mn/eris/local  /mnt       nfs        rsize=1024,wsize=1024   0    0
#use rsize=8192,wsize=8192 to increase performances
 
Mount an nfs from command prompt
/etc/init.d/portmap start
/etc/init.d/nfs start

[/etc/exports]
/mnt/nfs *(rw,insecure,sync,no_wdelay,insecure_locks,no_root_squash)

#The NFS share will be accessed with the privileges of nfsnobody
(ro,root_squash) 

#to re-read /etc/exports
service nfs restart
 
Unmount
#-l is force
umount -l /pippo