MySQL数据库迁移问题处理一则

                                 MySQL数据库迁移问题处理一则

  某日在做mysql迁移，使用的方法为冷拷贝所有数据文件到相同的版本的服务器上。目标服务器上
只是硬件配置要高，os和mysql本身的版本与源库的版本一致.

  当源库的data目录都拷贝到目标服务器后，使用mysqld_safe来启动mysqld时，发现总无法启动

[root@c12 goldengate]# /usr/local/mysql/bin/mysqld_safe --user=mysql --datadir=/usr/local/mysql/data
140109 14:20:26 mysqld_safe Logging to '/var/log/mysqld.log'.
140109 14:20:26 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data
140109 14:20:26 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

首先检查了一下pid-file目录是存在的，并且也有读写权限.

查看日志/var/log/mysqld.log

140109 14:20:26 InnoDB: Initializing buffer pool, size = 128.0M
140109 14:20:26 InnoDB: Completed initialization of buffer pool
InnoDB: The first specified data file ./ibdata did not exist:
InnoDB: a new database to be created!
140109 14:20:26  InnoDB: Setting file ./ibdata size to 10 MB
InnoDB: Database physically writes the file full: wait...
140109 14:20:26 InnoDB: Error: all log files must be created at the same time.
140109 14:20:26 InnoDB: All log files must be created also in database creation.
140109 14:20:26 InnoDB: If you want bigger or smaller log files, shut down the
140109 14:20:26 InnoDB: database and make sure there were no errors in shutdown.
140109 14:20:26 InnoDB: Then delete the existing log files. Edit the .cnf file
140109 14:20:26 InnoDB: and start the database again.
140109 14:20:26 [ERROR] Plugin 'InnoDB' init function returned error.
140109 14:20:26 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140109 14:20:26 [ERROR] Unknown/unsupported storage engine: InnoDB
140109 14:20:26 [ERROR] Aborting

最后面显示Unknown/unsupported storage engine: InnoDB,竟然innodb不支持.

难道这个版本上innodb使用有问题。在目标库上重新初始化了mysql,发现启动正常，innodb
没有任何问题

这下很无语了,当时时间有点紧，没有往出错的时候日志上看.再往上看显示的是

140109 14:20:26 InnoDB: Completed initialization of buffer pool
InnoDB: The first specified data file ./ibdata did not exist:
InnoDB: a new database to be created!

我们的方案是从源库拷贝所有数据文件过来的，在这里怎么还要创建./ibdata呢？想想肯定有参数定义错误了
最大的嫌疑对像是innodb_data_file_path

innodb_data_file_path=ibdata:10M:autoextend

仔细一看原来是漏了一个'1'忘掉了,正确的应该是  ibdata1:10M:autoextend.看来dba细心很重要啊.