How to add an extra second hard drive on Centos 7 LVM (XFS) and increase the size of storage

fdisk
n
p
enter / enter
wq

pvcreate /dev/
lvmdiskscan -l #show new disk info

Example: Extend VG:Centos, /dev/mapper/var
vgextend centos /dev/
lvm lvextend -l +100%FREE /dev/mapper/centos-var
xfs_growfs /dev/centos/var