错误详细内容如下：120220 10:16:48 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120220 10:16:48 [Warning] option 'max_allowed_packet': unsigned value 3221225472 adjusted to 1073741824
120220 10:16:48 [Note] Plugin 'FEDERATED' is disabled.
120220 10:16:48 InnoDB: The InnoDB memory heap is disabled
120220 10:16:48 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
120220 10:16:48 InnoDB: Compressed tables use zlib 1.2.3
120220 10:16:48 InnoDB: Using Linux native AIO
120220 10:16:48 InnoDB: Initializing buffer pool, size = 128.0M
120220 10:16:48 InnoDB: Completed initialization of buffer pool
InnoDB: Error: log file ./ib_logfile0 is of different size 0 104857600 bytes
InnoDB: than specified in the .cnf file 0 5242880 bytes!
120220 10:16:48 [ERROR] Plugin 'InnoDB' init function returned error.
120220 10:16:48 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
120220 10:16:48 [ERROR] Unknown/unsupported storage engine: InnoDB
120220 10:16:48 [ERROR] Aborting
可以修改mysql 的配置文件。
如果innodb_log_file_size = 100M这句话被注释掉了，请去掉前面的注释符后重启 mysql。
一般来说能修复 mysql 启动的日志大小错误。