Physical volume or Physical disk is the first layer of the disk management. It’s considered as physical DISKS connected to the system. It can be local to the system or from SAN storage. Normally Datacenter and storage team manage it. Any disk addition and expansion can be done if SPACE is available at this level.

A volume group is the second layer or middle layer between physical volume and logical volume. Volume group club all physical volume and display them as single storage to the system for further partitioning and USAGE. Due to large system in today’s environment, Application or Database need bigger space than an available physical disk. Volume group allows to clod multiple physical disk as one volume. This leverage system team to use bigger disks with any splitting at their end.

Logical volume or logical disk is the management of volume group to divide disk as per usage instead of allocation physical storage DIRECTLY. Logical Volume Management (LVM) PARTITIONS can allocate across the physical drives and be resized like traditional disks.