So I am getting docker size warnings, so looking to clean stuff up, but can't find what could be taking up space. I do see that stuff in /var/lib/docker/btrfs/subvolumes is 90% of space, but when I look at sizes of volumes, images, and containers I don't see anything this big. I also used https://github.com/SpaceinvaderOne/Unraid_check_docker_script/blob/main/Unraid_check_docker_script.sh but again didn't see anything. I did see reference to old (5+ year) old bugs in btrfs that had stale, duplicated data, but am not sure if that is still relevant. What can I do to see what to clean up?

You can always recreate the image and see if the used space decreases.

1 hour ago, JorgeB said:

You can always recreate the image and see if the used space decreases.

I would rather not have to delete all my images, and start again.

Did you see the link? It takes a few seconds to restore everything.

14 minutes ago, JorgeB said:

Did you see the link? It takes a few seconds to restore everything.

Yes I read the link, but what I read was you basically delete the img, and then reinstall the apps, which is what I don't want to do as I have some custom docker images that I don't want to have to rebuild.

 

Regardless, would like to know what is taking the space anyway, as I don't want to deal with this again in the future. Should I rebuild to use standard directory, or xfs?

13 minutes ago, Bob Cadenza said:

would like to know what is taking the space anyway

Cannot help with that, someone else might.

Ok so I have learned some. Firstly using du -sh inside /var/lib/docker the btrfs stuff doesn't get calculated correctly, so I have found that

docker system df --format 'There are \t {{.TotalCount}} \t {{.Type}} \t taking up ......{{.Size}}'

shows the best account of the space used. In my case I had a large amount of build cache, so after deleting the build cache, I was able to clear a lot of space.