"Logical volume management (LVM) is a way systems can abstract physical volume management into a higher-level and usually simpler paradigm. By using LVM, all physical disks and partitions, no matter what size and how scattered they are, can be abstracted and viewed as a single storage source. For example, in the layout of physical-to-logical mapping shown in Figure 1, how could the user create a filesystem of, say 150GB, since the biggest disk is 80GB large?
"By aggregating partitions and whole disks into a virtual disk, LVM can sum small storage spaces into a bigger, consolidated one. This virtual disk, in LVM terms, is called volume group..."