环境：

  192.168.91.103 数据源服务器
  192.168.18.220 异地备份服务器

1.在192.168.91.103服务器生成秘钥文件

[root@Lenovobox3 file]# ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):    #回车
Enter passphrase (empty for no passphrase):     #输入当前系统的密码
Enter same passphrase again:             #重复
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
......

2.将公钥文件下发至异地备份服务器

[root@Lenovobox3 file]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.18.220
The authenticity of host '192.168.18.220 (192.168.18.220)' can't be established.
ECDSA key fingerprint is e1:98:4f:fd:c9:12:4d:4a:c8:b5:a5:c5:77:0c:65:ea.
Are you sure you want to continue connecting (yes/no)? y
Please type 'yes' or 'no': y
Please type 'yes' or 'no': yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are 
already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to 
install the new keys
root@192.168.18.220's password:    #输入异地备份服务器密码

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.18.220'"
and check to make sure that only the key(s) you wanted were added.

3.进行备份测试，当前IP是192.168.91.103

[root@Lenovobox3 file]# ls
backup_test.txt
[root@Lenovobox3 file]# pwd
/root/file

4.连接至异地备份服务器192.168.18.220，执行备份

[root@localhost ~]# rsync -avzp -e 'ssh -p 22' root@192.168.91.103:/root/file/backup_test.txt /data
receiving incremental file list
backup_test.txt

sent 30 bytes  received 90 bytes  240.00 bytes/sec
total size is 5  speedup is 0.04

5.验证备份数据

[root@localhost ~]# cd /data/
[root@localhost data]# ls
backup_test.txt
[root@localhost data]# cat backup_test.txt 
test

6.设置备份脚本

[root@localhost data]# vim backup.sh 
rsync -avzp -e 'ssh -p 22' --delete root@192.168.91.103:/data/ball/dirmap/database /data/103

7.设置定时任务

[root@localhost data]# crontab -e
0 0 *  * 6 /data/backup.sh > /data/log/log$(date +\%Y\%m\%d).txt