Docker Image File Getting Full - Where has the space gone?

[TheImmatureAdmin]

Hi all, I have found a lot of topics similar to this but still haven't found my answer/solution. I hope I'm missing something easy.

 

UNRAID: 6.12.10

Docker image size: 50GB

Problem Description: My docker image is getting full, and seems to keep growing even though I'm not adding more containers. Eventually, I have issues because there is no free space. Typically, this is because of logs that are growing out of control, misconfigured paths, etc. So far, I haven't found anything that is misconfigured and my log sizes look reasonable. 

 

One thing I haven't figured out that would help me troubleshoot is, how do I ever find what is using this space? Knowing the container would greatly simplify the problem. I am running ~35 containers currently, and based on the measurements from using the "Container Size" tool, I'd expect at most around 23GB used out of 50GB, but I'm using now 44GB+. Below are screenshots from the Docker tab > Container Size output and from the Dashboard showing Docker image usage. 




 

I've also found a script from SpaceInvaderOne that gives more detailed data on docker image disk space usage, however it appears to align with the "Container Size" tool. I am still not seeing where the extra 20GB of data is being used.

Please let me know if I can provide any additional information. Thank you!

 

 

[TheImmatureAdmin]

For anyone curious, I found this old thread and the 'docker volume prune' command worked for me. I anticipate the size to keep growing until I find root cause, but for now it worked.

https://forums.unraid.net/topic/103674-solved-kinda-high-docker-utilization-but-container-size-doesnt-match/

 

 

For more context, I ran 'docker system df' with these results:

 

89 local volumes seemed like a high number with only 3 in active use. I decided to go ahead and try the 'docker volume prune' command even though only ~1.8GB seemed to be reclaimable. The result showed "total reclaimed space: 1.449GB", but checking the dashboard in Unraid now shows only 23.1 GiB usage when I was sitting at 44+ GiB before executing the prune command. That command got me back over 20GB. 

 

 

There still is the mystery of how that space is getting filled up, but at least I can clear it out now manually as needed.