Logical Volume Management (LVM)

• The Below illustration shows the relationships between disks, physical volumes (PVs), volume Groups (VGs) and Logical volumes in LVM:
• Volume management is a approach dealing with disks & partitions. The new approach to deal with this partitions is called as Logical Volume Management (LVM)
• Benefits of using LVM
  1. Greater flexibility for disk partitioning
  2. Easier online resizing of volumes
  3. Use of Snapshots
• Terms:
  • Physical Volume(PV): This represents physical disk.
  • Volume Group (VG): VGs are used to house one or more physical volumes & logical volumes into single administrative unit.
  • Logical Volume (LV): LVs are equivalent to disk partitions. LV appears as standard block device. LV can be mounted on to directories
  • Extents: Two kinds of extents physical extents & logical extents. PVs can be divided into physical extents. LVs can be divided into logical extents

Examining Disk Layout

• Open the parted prompt & execute print statement
• Physical volumes can be explored using pvdisplay & volume groups can be explored using vgdisplay & Logical volumes using lvdisplay
• Lets experiment
  • scan disks
  • Lets create a physical volume using pvcreate
  • Now lets create volume groups using vgcreate
  • Now lets create a Logical volume using lvcreate
  • Now create a file system in two lvs and mount it asper your needs