修改配置，MySQL启动报：[ERROR] The server quit without updating PID file

[root@localhost mysql]# /etc/init.d/mysqld start

Starting MySQL...

[ERROR] The server quit without updating PID file (/usr/local/mysql/data/mysqld.pid).
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查看错误日志发现：

   140306 14:13:40 [ERROR] /usr/sbin/mysqld: unknown variable 'rpl_semi_sync_master_enabled=1'
   140306 14:13:40 [ERROR] Aborting

 /etc/init.d/mysqld restart --plugin-load="rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so";

Shutting down MySQL.. SUCCESS! 
Starting MySQL.... SUCCESS!

另外，如果嫌这种写法比较麻烦还可以放在my.cnf里[mysqld]下，多个.so 可使用;隔开

plugin-load="rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so"

http://dev.mysql.com/doc/refman/5.5/en/server-options.html#option_mysqld_skip-grant-tables
http://dev.mysql.com/doc/refman/5.5/en/server-options.html#option_mysqld_plugin-load
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作者：freedom3959
来源：CSDN
原文：https://blog.csdn.net/lidan3959/article/details/20636237