"LVM supports enterprise level volume management of disk and disk subsystems by grouping arbitrary disks into volume groups. The total capacity of volume groups can be allocated to logical volumes, which are accessed as regular block devices.
Further, LVM provides logical separation of storage, the ability to move data from one physical device to another while on-line, and dynamic block device resizing. LVM also enables system administrators to upgrade systems, remove failing disks, reorganize workloads, and adapt to changing system needs, through a minimum amount of time and effort. "

The Logical Volume Manager for Linux