UUID partition was mystery to me – according to all documentation
available they make life easier instantly and you no longer have to worry about
your partition letters. Since I'm using LVM on all servers I manage I already
stopped worrying. But since this is preferred method now, I wanted to use it
(especially after last time udev created /dev/mapper/vg-lv device,
but no /dev/vg/lv device after boot and I realized that after my
backups were week old and I had to restore corrupted file :().
But here's the problem with UUIDs and LVM: After you create new LV, vol_id
and blkid will show their UUID. But as soon as you want to mount that LV via
/etc/fstab, it yields Special device UUID=... does not
exist. Today I learned this special command:
sudo partprobe
It updates the /dev/disk/by-uuid directory and your uuid mount works like a charm.