由于修改了远程服务器ＳＳＨ端口，在用rsync做数据同步时报如下错误：
[root@localhost mysql]# rsync -arz ./alldatabases_2017-10-30.sql root@120.2.17.90:/data/backup/13.3.21.14/
ssh: connect to host 120.24.174.90 port 22: Connection refused
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(605) [sender=3.0.9]
解决：需要增加参数-e，如下：
[root@localhost mysql]# rsync -arz -e 'ssh -p 65003' ./alldatabases_2017-10-30.sql root@120.2.17.90:/data/backup/13.3.21.14/
