Logical Volume Manager (LVM)

Lets consider we have 2 disks /dev/sdb1 and /dev/sdb2 of 10G each.

Creating Physical Volumes

pvcreate /dev/sdb1 /dev/sdb2

Creating Volume Manager

vgcreate myvol /dev/sdb1 /dev/sdb2

Creating Logical Volume

lvcreate -L 5G -n tools myvol

Applying File System

mkfs -t ext4 /dev/myvol/tools

Mounting the file system

mkdir /tools

mount -t ext4 /dev/myvol/tools /tools

To make the mount persistent over boot.

vi /etc/fstab
/dev/myvol/tools /tools ext4 defaults 0 0

To check the mounted partition

df -h

To check the physical volumes

pvs

To check the volume managers

vgs

To check the logical volumes

lvs

To view the details of a physical volume

pvdisplay /dev/sdb1

To view the details of a volume group

vgdisplay myvol

To view the details of a logical volume

lvdisplay tools

To extend the logical volume on the fly

lvextend -L +8G /dev/myvol/tools

resize2fs /dev/myvol/tools

To check the change

lvs
df -h

To reduce the logical volume

umount -v /tools

e2fsck -ff /dev/myvol/tools

resize2fs /dev/myvol/tools 10G

lvchange -an /dev/myvol/tools

lvreduce -L 10G /dev/myvol/tools

lvchange -ay /dev/myvol/tools

mount -a

To check the change

lvs
df -h

To remove a physical volume from volume manager

vgreduce myvol /dev/sdb2

To remove the complete logical volume

umount /tools

rm -f /tools

vi /etc/fstab (Remove the below entry)
/dev/myvol/tools /tools ext4 defaults 0 0

lvchange -an /dev/myvol/tools

lvremove /dev/myvol/tools

To remove the Volume Manager

vgremove myvol

To remove the Physical Volumes

pvremove /dev/sdb1 /dev/sdb2

To add a physical volume to the volume manager

vgextend myvol /dev/sdc1