My forum is hitting the limits of its server’s file system, but before upgrading the server I wanted to check there isn’t any config that would make it use the FS more efficiently. I have a standard install in /var/discourse, which is 20GB. But the /var/lib/docker folder is 21GB, most of which seems to be in “overlays” for the FS. I don’t understand how Docker works at the FS level, and I assume it’s not just carelessly duplicating data, but the two folders being so similar in size does make me wonder if there’s a chance the /var/discourse data has been copied into the Docker folder.

Have you done ./launcher cleanup It’s likely extra docker containers (so the answer to your question is yes)

I did run docker container prune, which didn’t do anything. The container list only shows the main app and the mail receiver. I also ran docker image prune which freed 1.5GB space. I didn’t think of running the launcher’s cleanup. Will try and report back.

Is Docker duplicating data?

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Dannii (Dannii) November 28, 2023, 6:33am 4

launcher cleanup cleaned up 6.6GB of images (I’m not sure why docker image prune didn’t remove them!), and also removed a 3.4GB Postgresql ‘backup data cluster’. So that will give us enough space for a while.

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Is Docker duplicating data?

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