1.建立ssh免登陆
ssh-keygen
ssh-copy-id -i ~/.ssh/id_rsa.pub root@xxx.xxx.xxx.xxx

2. 验证ssh（出现日期则成功）
   ssh xxx.xxx.xxx.xxx date
   2.开始Xtrabackup远程备份
   innobackupex --stream=tar ./ | ssh mysql@xxx.xxx.xxx.xxx \ "cat - > /data/date +"%Y%m%d_%H%M%S".tar"