Disk Looks something like this :
[root@oid ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda1 1252632 409940 778032 35% /
/dev/hda7 505604 480539 0 100% /home
/dev/hda3 1019240 153740 812888 16% /var
/dev/sde1 6190664 147668 5728528 3% /tmp
/dev/hda5 2030736 35880 1890036 2% /oem
/dev/hda2 3050092 1291860 1600796 45% /usr
tmpfs 3932160 0 3932160 0% /dev/shm
/dev/mapper/xen--vm-xen_prov
464455440 202872 440659608 1% /xen
[root@oid ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda1 1252632 409940 778032 35% /
/dev/hda7 505604 480539 0 100% /home
/dev/hda3 1019240 153740 812888 16% /var
/dev/sde1 6190664 147668 5728528 3% /tmp
/dev/hda5 2030736 35880 1890036 2% /oem
/dev/hda2 3050092 1291860 1600796 45% /usr
tmpfs 3932160 0 3932160 0% /dev/shm
/dev/mapper/xen--vm-xen_prov
464455440 202872 440659608 1% /xen
1) Take a backup of /etc/fstab
#cp /etc/fstab /etc/fstab.orig
2) edit /etc/fstab with below line
<partition as show in df output> <monted on> <filesystem>
/dev/mapper/xen--vm-xen_prov /xen ext3 defaults 0 2
