One day I noticed that a lot of my media-files were gone. And when checking the SMART, I can see that one drive has got a red SMART-light. This is the self-test:
TLDR, there is a read failure.
I guess some parts of the disk is unreadable.
When looking on my specific disk in the file browser I can see that there are still files available, and the disk is not empty.
I am using UnionFS, how do I swap this disk out and transfer the files that are good from the bad disk?