I had some old hard disks with lvm, without partitions. I.e. the whole disk were formatted as LVM physical volumes, and they didn't contain any partition tables.
I've backed them up, with sector-level copy (
dd) into lvm logical volumes.
The result is that now some of my logical volumes are also physical volumes, containing other logical volumes on them.
LVM works well, it detects them and I could use them (being backups, I practically don't use them, but I still need them).
I find this multi-level lvm structure a little bit sub-optimal, so I want to move them "out" of a layer, and convert them into top-level volumes.
Of course I could do this by creating top-level LVs with the same size and name, and copy the second-level LVs with
dd into them. But I would like to prefer to do it on an "LVM way", i.e. purely with lvm commands.
As far I know, there are (not very easy) ways to combine LVM VGs, but I fear maybe they would create lockups in such an lvm-over-lvm constellation.
Is it possible to do it, and how?