There was a case where one of my CentOS servers running out of space at the root which is mapped to /dev/sda5. I didn’t think I was using it much but the
df -h was telling me otherwise. So here is what I did.
$ cd / $ sudo du -h --max-depth=1
The command shows which directory is taking up how much space in human readable format. Thanks to that, I figured out what the problem was. 🙂