xtrabackup备份报错

Question

[root@node1 mysql]# innobackupex --user=root --passwor=redhat /root/backup/

140619 18:20:08  innobackupex: Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup' as 'root'  (using password: YES).
innobackupex: Error: Failed to connect to MySQL server: DBI connect(';mysql_read_default_group=xtrabackup','root',...) failed: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) at /usr/bin/innobackupex line 2995
我看网上说安装perl-DBD-MySQL，可以解决，但是我安装过后，一样出现此问题。

PS：MySQL的版本是5.6.16，自己编译安装的。