Extend Partition
From KlavoWiki
To extend the size of a partition for CentOS. This only works if it is the last partition in the list. This can be accomplished for standard or extended partitions.
Delete the partition and then re-create but make sure the starting point is the same.
If a GPT disk move the GPT Header to the end of the disk.
gdisk /dev/sda x – Enter the expert menu. e – Relocate the GPT header to the end of the disk. m – return to the previous menu.
xfs_growfs /dev/sda5
or depending on your partition type.
resize2fs /dev/sda5