报错：
[root@DB dbdata]# innobackupex --defaults-file=/etc/my.cnf --user=root --password=123 /data/dbdata
InnoDB Backup Utility v1.5.1-xtrabackup; Copyright 2003, 2009 Innobase Oy
and Percona Inc 2009-2012. All Rights Reserved.
This software is published under
the GNU GENERAL PUBLIC LICENSE Version 2, June 1991.
160615 02:23:17 innobackupex: Starting mysql with options: --defaults-file='/etc/my.cnf' --password=xxxxxxxx --user='root' --unbuffered --
160615 02:23:17 innobackupex: Connected to database with mysql child process (pid=10545)
160615 02:23:23 innobackupex: Connection to database server closed
IMPORTANT: Please check that the backup run completes successfully.
At the end of a successful backup run innobackupex
prints "completed OK!".
innobackupex: Using mysql Ver 14.14 Distrib 5.5.40, for Linux (x86_64) using readline 5.1
innobackupex: Using mysql server version Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
xtrabackup: Error: Please set parameter 'datadir'
innobackupex: fatal error: no 'mysqld' group in MySQL options
innobackupex: fatal error: OR no 'datadir' option in group 'mysqld' in MySQL options
解决方案：的my.cnf中加入datadir=/usr/local/mysql/data/(根据实际情况定目录的位置)
[root@v01-svn-test-server 2016-06-21_10-48-20]# grep "datadir" /etc/my.cnf datadir = /alidata/server/mysql-5.5.40/data/