RHEL 7 - Extend root filesystem (type xfs)

# fdisk -l
Disk /dev/sdb: 5368 MB, 5368709120 bytes

# fdisk /dev/sdb
Command (m for help): n (new)
Select (default p): p (primary)
Partition number (1-4, default 1): 1 (choose default 1)
Partition 1 of type Linux and of size 5 GiB is set
Command (m for help): t (change type)
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): w
The partition table has been altered!

# pvcreate /dev/sdb1
  Physical volume "/dev/sdb1" successfully created.

# vgextend rhel /dev/sdb1
  Volume group "rhel" successfully extended

# vgdisplay rhel
  Free  PE / Size       1279 / <5.00 GiB

# pvscan
  PV /dev/sda2   VG rhel            lvm2 [<7.00 GiB / 0    free]
  PV /dev/sdb1   VG rhel            lvm2 [<5.00 GiB / <5.00 GiB free]
  Total: 2 [11.99 GiB] / in use: 2 [11.99 GiB] / in no VG: 0 [0   ]

# lvextend /dev/rhel/root /dev/sdb1
  Size of logical volume rhel/root changed from <6.20 GiB (1586 extents) to 11.19 GiB (2865 extents).
  Logical volume rhel/root successfully resized.

# xfs_growfs /dev/rhel/root
data blocks changed from 1624064 to 2933760

# df -h /
Filesystem             Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root   12G  5.6G  5.6G  50% /