extend root filesystem size on VM

1. Increase the space as required in vcenter.
2. fdisk -l /dev/sda (Check the new space reflected)
3. create new partition with fdisk /dev/sda
4. Need a restart to reflect the new partition (if required)
5. add new partition -
a) pvcreate /dev/sda4
b) vgextend vg_system /dev/sda4
c) lvextended -L +50G /dev/mapper/vg_system
d) resize2fs /dev/mapper/vg_system

df -h