If you check the binaryData folder in your container is there anything in it? Part of it could be the logging of workflows as well, Have you set up any database pruning options?
And please do not simply delete the issue template rather fill it. It is there for a reason, esp. the “Information on your n8n setup” section. That makes it easier to answer your question without having to ask more questions and so give you a meaningful and helpful answer.
Generally, can you reduce the data by configuring n8n so that it does not save successful executions. Executions and binary data get by default saved in the database (could be SQLite, which would fill up your local disk, or external database, which would fill up that disk) unless you have n8n configured to save binary data to the filesystem instead via N8N_DEFAULT_BINARY_DATA_MODE=filesystem.
If you want to save successful executions but just for a limited time and then prune automatically you can find a guide here:
The folder would be next to the database file in the volume you create, But I don’t think that option is enabled by default so they would stay in memory or that is my understanding anyway.
Have you done a search on the OS to find the largest folders that could show you where to look.
That screenshot tells us what is going on, The size is likely being taken up by the data being stored in the database. If you check your workflow settings you can set them to not log for every run and only log when events have failed. If you do need to log for everything then the server would need to be specced to deal with that.
It would also be worth setting the vacuum option which may help to free up some of the space once the execution data is deleted.