原本好好的服务器，安装了magento后mysql总会跪。
很奇怪之后查看日志，得到类似于：
Version: '5.5.44-0ubuntu0.12.04.1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)
151203 16:28:01 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
151203 16:28:01 [Note] Plugin 'FEDERATED' is disabled.
151203 16:28:01 InnoDB: The InnoDB memory heap is disabled
151203 16:28:01 InnoDB: Mutexes and rw_locks use GCC atomic builtins
151203 16:28:01 InnoDB: Compressed tables use zlib 1.2.3.4
151203 16:28:01 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
151203 16:28:01 InnoDB: Completed initialization of buffer pool
151203 16:28:01 InnoDB: Fatal error: cannot allocate memory for the buffer pool
151203 16:28:01 [ERROR] Plugin 'InnoDB' init function returned error.
151203 16:28:01 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
151203 16:28:01 [ERROR] Unknown/unsupported storage engine: InnoDB
151203 16:28:01 [ERROR] Aborting
151203 16:28:01 [Note] /usr/sbin/mysqld: Shutdown complete
我一百度说的五花八门，还有说设置临时目录的。。。=.=b
其实是mysql默认关闭了federated引擎。进mysql之后执行
show engines;
就会看到federated的support状态是no
解决办法为修改配置文件my.cnf，在[mysqld]
下面增加
federated
重启mysql服务就正常了。
Ubuntu15.10 Kylin安装MySQL 5.7.9：http://www.linuxdiyf.com/linux/16137.html
在Ubuntu上安装Mysql并远程连接：http://www.linuxdiyf.com/linux/15568.html
Ubuntu15.04的MySQL数据库允许Toad远程连接：http://www.linuxdiyf.com/linux/12995.html
Linux下查看MySQL的安装路径：http://www.linuxdiyf.com/linux/14760.html
ubuntu15.04手动安装MySQL5.6.27数据库：http://www.linuxdiyf.com/linux/14699.html