Xtrabackup做备份时遇到下面错误信息MySQL server: Can't connect to local MySQL server through socket '/tmp/mysql.so‘（2）
[root@MySQL-DB ~]# innobackupex --defaults-file=/usr/my.cnf --user=root --password=password /mnt/resource/mysql_backup160322 22:28:43 innobackupex: Starting the backup operation
IMPORTANT: Please check that the backup run completes successfully.
At the end of a successful backup run innobackupex prints "completed OK!".160322 22:28:43 version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup' as 'root' (using password: YES).
Failed to connect to MySQL server as DBD::mysql module is not installed at - line 1327.
160322 22:28:43 Connecting to MySQL server host: localhost, user: root, password: set, port: 0, socket: (null)
Failed to connect to MySQL server: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2).
出现这种情况是因为我修改了my.cnf中参数datadir，但是没有修改socket参数（参数为空），所以出现这个错误。另外我估计更换MySQL数据目录后,如果没有正确配置也会出现这个错误. 我们首先找到对应的mysql.sock文件位置，然后修改my.cnf中的参数scoket值，重启MySQL服务即可解决
[root@MySQL-DB mysql_backup]# find / -name "mysql.sock"/var/lib/mysql/mysql.sock
另外，其实我这篇文章ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)里介绍的建立软连接也可解决这个问题。
另外，在网上也有种偏方解决这个问题，即指定--host=127.0.0.1也可避免这个错误，我测试确实也能解决问题。不过这个是个治标不治本的方法.
innobackupex --defaults-file=/usr/my.cnf --user=root --password=password --host=127.0.0.1 /mnt/resource/mysql_backup
参考资料：
http://www.cnblogs.com/fuhj02/p/3541173.html