Restoring a broken LVM cache

October 31, 2012
  1. A working LVM setup - e.g. lvdisplay shows something
  2. /sbin/dmsetup remove_all (or similar)
  3. lvdisplay (or any) will now say “No volume groups found”
  4. Similarly, pvdisplay won’t even find your drives

You can get this back with lvm pvscan, lvm vgscan and lvm lvscan (for whatever you broke).