Create and Extend LVM Volume in Linux RHEL

Create LVM Volume

Creating the Physical Volumes

To use disks in a volume group, you label them as LVM physical volumes.
# fdisk /dev/sdb
n => p => 1 =>Start:? => Last:? => t => 8e => w

Creating the Volume Group

The following command creates the volume group VGDATA .    

# vgcreate VGDATA /dev/sdb1  /dev/sdb2 ...

Creating the Logical Volume

The following command creates the logical volume new_logical_volume(DATA) from the volume group new_vol_group(VGDATA). This example creates a logical volume that uses 100% of the volume group.

# lvcreate -l 100%PVS -n DATA VGDATA /dev/sdb1

But if we need 2GB of volume group:

# lvcreate -L2G -n DATA  VGDATA 

Creating the File System

The following command creates a ext4 file system on the logical volume.

# mkfs -t ext4 /dev/VGDATA/DATA

Configure for auto mount LVM with startup OS

add configure below to /etc/fstab

/dev/VGDATA/DATA /DATA ext4 defaults 0 0

Mounting the File System

# mount /dev/VGDATA/DATA /DATA

Extend LVM Volume

Creating the new Physical Volumes

To use disks in a volume group, you label them as LVM physical volumes.
# fdisk /dev/sdc
n => p => 1 =>Start:? => Last:? => t => 8e => w

Extending a Volume

Add new physical volume
# vgextend VGDATA /dev/sdc1

Check VG increased
# vgs

Check free size of VG for increase
# vgdisplay
Free  PE / Size       12749 / 49.80 GiB

There are 12749 free PE available = 49.80GB Free space available. So we can expand our logical volume up-to 49.80GB more. Let us use the PE size to extend.
# lvextend -l +12749 /dev/VGDATA/DATA

After Extending, we need to re-size the file-system using.

# resize2fs /dev/VGDATA/DATA