Maybe you have experienced this when the server disk capacity is quite narrow and you have to delete files, but when you have successfully deleted a dozen Giga files for example, but the server disk remains unchanged.
The first thing you should do is try restarting your server first, and see if the server disk can change after the reboot process.
If not, you should install tune2fs.
# yum install tune2fs
Then once installed, run this command, making sure you are root.
syntax : tune2fs -m <number> <disk>
For example, if your server disk is /dev/vda1 then :
# tune2fs -m 1 /dev/vda1
Then check if your disk server has now changed.