创建虚拟内存

mkdir /var/swap
dd if=/dev/zero of=/var/swap/swap_1G bs=2048 count=524288
chmod 0600 /var/swap/swap_1G
mkswap /var/swap/swap_1G
swapon /var/swap/swap_1G

开机启动：
echo "/var/swap/swap_1G swap swap default 0 0" >> /etc/fstab

检查:
free --si -h