Today I was confused about the missing disk space on my development
machine. I ran ncdu / only to find out that a lot of the disk is
used by docker volumes.
So I began investigating which volumes are actually taking this much space:
docker system df -v
Which showed a lot of local volumes that were taking a lot of GB. These were the result of containers which mounted volumes to the wrong endpoint within the container, so that the volumes grew heavily.
I deleted the largest container first (40 GB):
docker volume rm <VOLUME_NAME>
But then decided to find dangling volumes:
docker volume ls -q -f dangling=true
These can be easily removed via:
docker volume rm `docker volume ls -q -f dangling=true`
This should be executed from time to time, to remove volumes which surreptitiously took a lot of your disk space.