Chapter 2. What is Logical Volume Management?
Logical volume management provides a higher-level view of the disk
storage on a computer system than the traditional view of disks and
partitions. This gives the system administrator much more flexibility
in allocating storage to applications and users.
Storage volumes created under the control of the logical volume
manager can be resized and moved around almost at will, although this
may need some upgrading of file system tools.
The logical volume manager also allows management of storage volumes in
user-defined groups, allowing the system administrator to deal with
sensibly named volume groups such as "development" and "sales" rather
than physical disk names such as "sda" and "sdb".