Hey, thanks for the reply.
All the answers to your questions can be taken from the screens I attached to my first post.
But here is the info you seek:
Disk full? No, each disk has 5+TB free space
Allocation method: Most-free
Split level: Automatically split any directory as required
Minimum free space: 100GB
I mean it works for now, after trying to copy the files to the upper directory. I don't know if this triggered something that fixed my problem. Just wanted to know why I had it in the first place.
Concerning shares: I'd like one share for media and subfolders for movies, tv shows etc.. Is there any reason this is not recommended?