For some (yet unknown) reason, I've created a folder on my gluster share that's behaving strangely...
After having the same files on multiple bricks, showing them multiple times when listing over mounted glusterfs, I decided to remove it and copy it again.
I've had to remove it on brick-level, because the folder couldn't be touched over glusterfs.
Since then, the folder is gone, but when I tried to create it again, I got:
Although it doesn't exist.mkdir: cannot create directory `/mnt/dlp-storage/part2/video/12': File exists
[SOLUTION]
I must admit, I forgot that we have more than 1 node - so we have more than just the local bricks to wipe.
I've unmounted all glusterfs shares, then removed the affected folder from *all* bricks on all nodes. Then remounted the gluster share, and I was able to create and sync the folder again - without problems.
Puh. Lucky me, it was just a human error