Sometimes we may have faced the issue that the disk space not updating even after clearing data.
Mostly this will be due to the deleted process that still using the space. This can be traced and solved by the steps mentioned in the following url.
But in some cases this will not help to recover the space back.
This is because of the reserved space in Linux systems. We can recover it back using the following command.
#tune2fs -m 1 <DEVICE>
Here we need to replace the DEVICE with the corresponding disk ids.