Creating and deleting logical volumes by size (-L) or extent count (-l) (lvcreate, lvremove, lvs)

Logical volumes (LVs) are the top layer of LVM and the part you actually use: you put a file system or swap on an LV and mount it, just as you would a partition. The difference is flexibility. An LV is allocated from a volume group's pool, can span several disks, and can be extended later without repartitioning.