为什么删除 docker 容器和图像不会释放 Windows 上的存储空间？ 如何解决？

Question

Problem:

As I download and run containers, they keep taking up more and more space. I found suggestions for cleaning up unused containers and images and I did so. Guess what? They eat up even more disk space

What I found so far:

It has to do with .docker\machine\machines\default\disk.vmdk file. It only gets bigger

Log of disk.vmdk:

                            size (MB)
1. with 2 images                1,376
2. downloading a new image X    ?
3. running X as Y               2,963
4. removing Y                   2,963
5. removing X                   3,106
6. removing all the images      3,126

The only fix I found so far was running docker-machine rm default which removes the VM. The problem is that I have to download all the images again. There should be a better fix. Can someone explain:

1. What is going on?
2. How to fix it?

Answer 1

There are maintainance commands you can run on the more recent versions of Docker. They will free up space used by stopped containers, dangling images and dangling volumes:

docker container prune -f
docker image prune -f
docker volume prune -f

Answer 2

Maybe the images you are using, use volumes. If they do then deleting the container doesn't do the trick. You must delete the volumes as well. In order to do that you must specify the -v flag when deleting a container

docker rm -v <container name or container id>

Depending on your docker version you will have some more commands available. Check this SO thread for more. You can read more about orphaned volumes in this SO thread

Answer 3

After deleting all the unwanted containers and images using the commands below:

• Docker container rm
• Docker image rm
• Docker container prune
• Docker image prune
• Docker volume prune

I couldn't see any disk space released. I found out the disk space was released after I restarted my Docker desktop.

Answer 4

On windows 10, this was a major issue, space was not freeing up, even after I ran docker system prune I started noticing this when I found that every week; my SSD was filling up every2 or 3 GB of space.

Try opening Docker Desktop, hitting the Troubleshoot icon at the top right of the UI, and then clicking "Clean / Purge data". This reclaimed the space for me.

Also see:

1. Windows 10: Docker does not release disk space after deleting all images and containers #244
2. Hyper V ui issue fix
3. Clear Hyper-V recognize unused sectors
4. Linux growing docker size issue fix

Answer 5

If anyone is struggling with this problem on Ubuntu:

In my case pruning and removing using the docker command did not help much.

The issue was docker/overlay2 folder.

febrin@laptop:/var/lib$ sudo du -sh docker/overlay2
361G    docker/overlay2

I had to delete it manually.

Answer 6

On windows using wsl2 follow the below steps. Note that you will lose all the docker images and containers if you follow this. If you want to retain data(images and containers) then you can try the prune option mentioned by other people on this thread.

Locate the vhdx file where docker stores the data. This is a virtual hard disk used by docker.

"P:\Users\your-username\AppData\Local\Docker\wsl\data\ext4.vhdx"

In my case docker is using up about 27GB of disk space in this file. Even after deleting all the images and container, docker is not releasing the free disk space back to OS.

To reclaim the disk space, you have to try clean/purge data option from the GUI. When prompted for the data set name, select WSL 2. This should clean up and give back all the unused space.

In case, the docker daemon doesn't start up or disk space is not reduced then the last option is to factory restore from docker desktop GUI like show below.