I used your my.cnf wizard to optimize mysql on a domU xen server. The server is running centos 6.5. After copying and pasting the result into my.cnf, I couldn’t restart mysql and was obliged to return to the default my.cnf.
140810 21:21:00 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql/
140810 21:21:00 InnoDB: Initializing buffer pool, size = 128.0M
140810 21:21:00 InnoDB: Completed initialization of buffer pool
InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes
InnoDB: than specified in the .cnf file 0 67108864 bytes!
140810 21:21:00 [ERROR] Plugin ‘InnoDB’ init function returned error.
140810 21:21:00 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
140810 21:21:00 [ERROR] Unknown/unsupported table type: InnoDB
140810 21:21:00 [ERROR] Aborting
140810 21:21:00 [Note] /usr/libexec/mysqld: Shutdown complete
140810 21:21:00 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended