I can see the used disk quota on server is 81G for partition /dev/sda3 mounted to '/' as follows.
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 106G 81G 20G 81% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
/dev/sda1 477M 52M 400M 12% /boot
tmpfs 1.0G 0 1.0G 0% /var/lib/mysqltmp
/usr/tmpDSK 4.0G 183M 3.6G 5% /tmp
But when Iam checking with the '/' directory by executing du -sh command it is taking only 17G of disk space, can any one advice where this remaining space is utilized, any advice ? Iam using CentOS release 6.7 (Final)