买了个阿里云的vps 装了一个wordpress，mysql一直自动关闭，百思不得其解，只有搜索
最后才发现是因为服务器内存太小,毕竟是最便宜的才512m
-----------------------------------------------------
InnoDB: mmap(137363456 bytes) failed; errno 12
140521 1:53:50 InnoDB: Completed initialization of buffer pool
140521 1:53:50 InnoDB: Fatal error: cannot allocate memory for the buffer pool
140521 1:53:50 [ERROR] Plugin 'InnoDB' init function returned error.
140521 1:53:50 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140521 1:53:50 [ERROR] Unknown/unsupported storage engine: InnoDB
140521 1:53:50 [ERROR] Aborting
140521 1:53:50 [Note] /usr/sbin/mysqld: Shutdown complete
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没有100M的空间给他使用，修改/etc/mysql/my.cnf
增加
[mysqld]
innodb_buffer_pool_size=8MB
保存后，再启动mysql
mysql -u root -p
进入mysql
输入
show variables like'%buffer_pool%';
看到
+------------------------------+---------+
| Variable_name | Value |
+------------------------------+---------+
| innodb_buffer_pool_instances | 1 |
| innodb_buffer_pool_size | 8388608 |
+------------------------------+---------+
说明成功了，这样就不会重启了，话说512m的内存真可怜。