Correct, however basically no one uses that. The MD (RAID) devices are much more common for that, including under boot drives.

See comparison on ServerFault.

If personal anecdote is good for anything, I’ve been using LVM on top of software RAID on Linux for close to 20 years now without ever losing a volume. The last time I lost data was on ReiserFS 3. Like I said, LVM does not protect against drive failure itself. That’s why I use RAID underneath. I’ve got my OS disk to protect against failures like that. Also frequent and verified backups of my data files to make sure that is protected.

And yes, modern (still supported) distros can scan LVM PVs on boot without issue.

LVM Physical Volumes (PV) can be moved between Linux machines without issue (I’ve done that several times), it’s not like hardware RAID where you have to have the same controller on both machines. Nothing I’ve done has ever required LVM metatata export/import.

LVM itself does not provide redundancy, that’s RAID. LVM is often used on top of a RAID device. If your boot drive fails, LVM itself won’t save you, RAID (software RAID 1 is really common for a boot drive) can.

LVM can be used to seamlessly move data between physical volumes. You can add a new PV to the VG and move extents between LVs. I’ve used it to love-migrate to a larger drive that way. Once the physical extents have been moved to the new PV, you can reduce the old PV and then remove the old disk.

Yes, it can see them because their parent directories are readable, but it can’t see anything inside /media/velummortis because the Other permissions are empty. If you run chmod 755 /media/velummortis then Jellyfin should be able to see those files

What are the permissions on the directory itself, not the files? Is the directory owned by group ‘video’?