Logical Volume Manager (LVM) Part I Basics

LVM stands for Logical Volume Management. It is a system of managing logical volumes or file systems, that is much more advanced and flexible than the traditional method of partitioning a disk into one or more segments and formatting that partition with a filesystem.

This article primarily related to HP-UX operating system. However other
operating systems may have their own peculiarities and nuances, but the basis
is certainly one.The disk that is part of the LVM has a specific structure and
contains service information.

LVM structure: one or more disks are combined into a Volume Group (VG)
within which you can create one or more Logical Volume (LV),  between
which to allocate the disk space of the volume group drives. On Logical Volume,
create file systems or swap areas and specify mount points.

Useful directories and files:
/DEV/DSK/CXTXDX and/DEV/RDSK/CXTXDX device files (block and raw)
of the hard drives in the system /dev/vgxxx/group -Device file for Volume 
group Vgxxx /dev/vgxxx/lvxxx  and /dev/vgxxx/rlvxxx -Logical volume
(block and raw) files from the Volume Group VGxxx, /etc/lvmtab is a binary
file that contains a list of the system's Volume Groups and a list of their hard
drives (physical volumes). Some of the information from the file can be viewed
by the strings command /etc/lvmconf -Directory with the backups of the Volume
Group configuration files. is updated with the volume Group or Logical volume
change commands or a single command - vgcfgbackup .
List of file systems and mount points used to automatically mount file systems
at the start of the OS, is a list of what is currently being installed. 

Information is used by the Mount/umount(2) and DF/BDF.

Logical Volume Manager (LVM) Part 2. Basics

Materials refer link