Docker image file filling up but containersize says there is plenty of space

[Mark12]

I am using Unraid 6.12.10. My docker.img file is on the cache drive.

I have already increased its size from 20-->30-->50GB and it is now again filling up.

I am using Nextcloud AIO, and some *arr apps, that's about it.

 

When I look at the docker sizes via the built-in "container size" button it says only ~8GB is used. This is confusing: I am getting alerts that my docker.img is full and I know this to be true since I am getting errors with my containers. How do I find out what is taking up this much space in my Docker image?

 

I have found several threads about this on the forums but none that go further then "check your mappings" and "use the container size button". My idea is: if the mappings where wrong I should see a large container when using "check container size" right?

tower-diagnostics-20240605-1148.zip

[Mark12]

Anyone that can help me solve this issue?

I am now unable to use my Nextcloud, it's not starting up.

The container size button still says I have plenty of space available...

[Mark12]

No one here that can help with this issue? There must be some way to find out what is eating all the space in the docker.img?

[JorgeB]

You should still check your mappings.

[Mark12]

31 minutes ago, JorgeB said:

You should still check your mappings.

Can you explain this to me? If I map it to the wrong directory, meaning it will fill up the docker .img why would that not show up in the docker image size button? Doesn't make any sence. How would it even know if the mapping is wrong or if it is delibirate?

[JorgeB]

Sometimes using the image size button doesn't show the problem, and if the image is growing, something is writing to it, hence:

1 hour ago, JorgeB said:

You should still check your mappings.

 

You can also try this to see if it identifies the culprit container:

https://github.com/SpaceinvaderOne/Unraid_check_docker_script

[Mark12]

Ok, for anyone who's wondering: it wasn't the mappings. I deleted ALL my docker volumes using docker system prune. After downloading only the Nextcloud AIO image I got a message stating docker.img was ful.

 

After some more research I found that the btrfs subvolumes are not cleaned up under ls /var/lib/docker/btrfs/subvolumes the command "ls /var/lib/docker/btrfs/subvolumes | xargs btrfs subvolume delete" fixed it for me!