swapoff /dev/mapper/dmgroup-lvswap
lvreduce -L -54.5G /dev/mapper/dmgroup-lvswap
mkswap /dev/mapper/dmgroup-lvswap
swapon /dev/mapper/dmgroup-lvswap
lvextend -L +54G /dev/mapper/dmgroup-lvroot
resize2fs -p /dev/mapper/dmgroup-lvrootcentos
##### -54.5G是針對swap來作的和+54G是針對根目錄來作的,操做系統版本centos6.7app