迁移的网站生成文档到三分之一左右的时候报错：

Error infos:DedeCms错误警告：连接数据库失败可能是数据库密码不对或数据库服务器出错！

火大，登陆MySQL发现

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'

service mysqld restart 重启失败:mysql daemon failed to start

cat /var/log/mysqld.log 发现：

 [NOTE] InnoDB: Initializing buffer pool, size = 128.0M

 [NOTE] InnoDB: mmap(137363456 bytes) failed; errno 12

 [ERROR] InnoDB: Cannot allocate memory for the buffer pool

 [ERROR] Plugin 'InnoDB' init function returned error.

 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.

 [ERROR] Unknown/unsupported storage engine: InnoDB

 [ERROR] Aborting

问题找到，分配不了足够的内存，

vim /etc/my.cnf

innodb_buffer_pool_size=100M

service mysqld start --------ok

搞定