Why did nextcloud run out of space?

Question

ubuntu

I assembled a regular computer, for a very long time and I don’t remember what is there and how, I remember that there are 2 hdd ~ 400 GB each, they are in the raid, but I don’t remember exactly how I did it

now I ran into the fact that the space ran out, in fact the files take up 80 GB (basket empty)

who will tell you how and where to dig?