Used Space is much higher than actual space used in the partition

Question

Hi All,
I am facing space problem in oracle Linux 5.3.
The parition /oradata is showing Used space as 379 GB when checked with df -TH command and when i go to partition and check space with du -sh command it is showing 280 GB.
How could i reclaim the space.
[orah@hih oracle]$ df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda3 ext3 16G 1.0G 14G 7% /
/dev/sda4 ext3 11G 2.9G 6.8G 31% /usr
/dev/sdb5 ext3 11G 158M 9.5G 2% /tmp
/dev/sdb3 ext3 51G 189M 48G 1% /orasig
/dev/sdb2 ext3 11G 277M 9.4G 3% /var
/dev/sdb1 ext3 71G 12G 56G 17% /oracle
/dev/sda1 ext3 104M 16M 83M 17% /boot
tmpfs tmpfs 26G 9.6M 26G 1% /dev/shm
/dev/sdc ext3 529G 379G 140G 74% /oradata
/dev/sdd ext3 529G 401G 128G 76% /orabkp
/dev/sde ext3 212G 197G 14G 94% /oraprod1
/dev/sdf ext3 119G 73G 45G 63% /stage
Rgds,
Alig

Answer 1

What is your output of df -h?
-H uses powers of 1000, not 1024. Computer memory uses binary logic based on the power of 2 (2^10 = 1024, 8 * 8 * 8 * 2 = 1024)
Anyway, df and du measure different things:
"du" reports the space used by files and folders
"df" reports the space used by the file system, which includes the overhead for journals and inode tables.
If a file is open by a user and the same file is deleted then df and du will report different output.
A reboot of the system should align df and du output more closely.