Glossary

• Physical Volume (PV) - A disk (or any block device).
• UUID - A unique ID assigned to a physical volume by the LVM sub-system. The UUID is stored on the physical volume (as the last signature).
• Volume Group (VG) - A set of physical volumes.
• Physical Extent (PE) - The minimal chunk on a physical volume that is managed by LVM.
• Logical Volume (LV) - A "virtual" block device, that is created by LVM on some volume group. The logical volume is mapped to a list of physical extents, that may reside on any of the volumes in a single volume group.
• Snapshot - A (logical) freeze of a logical volume at some point in time. enables us to revert changes made to a logical volume since the snapshot was taken.

Originally written by guy keren