Check Linux Disk Usage
You may have encountered the situation that your Linux system is running out of space. This happens more often on embedded devices running on a small eMMC or SD card. To cleanup the system, you first need to find out what is taking up the space.
- Check partitions
With this command you will know which partition is full.
- Check file/folder within a partition
With this command you will know which file/folder is taking up the space.
-  https://askubuntu.com/questions/266825/what-do-i-do-when-my-root-filesystem-is-full