mysql编译安装完启动时候报错

[root@host2 mysql]# /etc/init.d/mysqld start
Starting MySQL. ERROR! The server quit without updating PID file (/tmp/mysql.pid).

[root@host2 mysql]# tail -f data/host2.err
InnoDB: Error: log file ./ib_logfile0 is of different size 0 4194304 bytes
InnoDB: than specified in the .cnf file 0 5242880 bytes!
170310 17:06:48 [ERROR] Plugin 'InnoDB' init function returned error.
170310 17:06:48 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
170310 17:06:48 [ERROR] Unknown/unsupported storage engine: InnoDB
170310 17:06:48 [ERROR] Aborting

170310 17:06:48 [Note] /application/mysql/bin/mysqld: Shutdown complete

170310 17:06:48 mysqld_safe mysqld from pid file /application/mysql/data/host2.pid ended

说函数误差
解决方法：
把data下面的ib_logfil文件删除即可
[root@host2 mysql]# rm -f data/ib_logfile0
[root@host2 mysql]# rm -f data/ib_logfile1
[root@host2 mysql]# rm -f data/ib_logfil2