RAID 1 (Mirror) with LUKS encryption missing after reboot / edit of config.xml

Thanks for your input.
I won't use an array again, I'll just rsync the data in the future (which I'm planning to do to a remote Pi-based OMV anyways). As said, luckily I do have a backup which is only one, maybe two weeks old and thinking about it I will probably only lose cell phone pictures of that timespan - in the original format, I have a backup of those in reduced size via Google.

So I'll just stop here. Thank you all for all your help, although we couldn't fix the problem - I'll just live with it.
And always remember kids, have a backup of your backup - otherwise I wouldn't yet come to that decision.

Thanks for the reminder - I have them regularly checked anyways, though.

Oh one more question: How do I remove a missing file system in OMV?
In FileSystems the device /dev/disk/by-label/RAID4TB is still there, but I can't delete it, at least not using the GUI.

(It's greyed because Filesystem creation is in the foreground)

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edit
Nevermind - I had to delete the shared folders (after deleting the references), then it was no problem to delete the filesystem as well.