Troubleshooting Disk Usage in Linux

Track down which partition is the problem.

df -h

How to tell what's taking up the most space?

du -chx --max-depth=1 /

The output will look something like this:

4.0K    /media 40M     /etc 262M    /home 0       /dev 3.3G    /usr 4.0K    /selinux 4.0K    /srv 2.2G    /var 7.7M    /bin 0       /misc 1.4M    /tmp 12K     /mnt 0       /proc 41G     /opt 27M     /lib64 0       /sys 0       /net 16K     /lost+found 394M    /lib 133M    /root 15M     /sbin 4.0K    /boot 48G     / 48G     total

Then you can go deeper and deeper until you find the culprit:

du -chx --max-depth=1 /opt
du -chx --max-depth=1 /opt/...