Migrated a lvm space to a swap memory on CentOS 7
1. lvmdisplay to get lv path
2. lvreduce -L -8G /dev/centos /dev/centos/sharedisk
3. lvcreate -L 8G -n lvswap centos # centos is VG Name
4. mkswap /dev/centos/lvswap
5. swapon -a
2. lvreduce -L -8G /dev/centos /dev/centos/sharedisk
3. lvcreate -L 8G -n lvswap centos # centos is VG Name
4. mkswap /dev/centos/lvswap
5. swapon -a