查看mysql错误提示
170329 08:26:23 mysqld_safe Number of processes running now: 0 170329 08:26:23 mysqld_safe mysqld restarted 170329 8:26:23 [Note] /usr/local/mysql/bin/mysqld (mysqld 5.5.48-log) starting as process 4353 ... 170329 8:26:23 [Note] Plugin 'FEDERATED' is disabled. 170329 8:26:23 InnoDB: The InnoDB memory heap is disabled 170329 8:26:23 InnoDB: Mutexes and rw_locks use GCC atomic builtins 170329 8:26:23 InnoDB: Compressed tables use zlib 1.2.3 170329 8:26:23 InnoDB: Initializing buffer pool, size = 4.0G InnoDB: mmap(4395630592 bytes) failed; errno 12 170329 8:26:23 InnoDB: Completed initialization of buffer pool 170329 8:26:23 InnoDB: Fatal error: cannot allocate memory for the buffer pool 170329 8:26:23 [ERROR] Plugin 'InnoDB' init function returned error. 170329 8:26:23 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 170329 8:26:23 [ERROR] Unknown/unsupported storage engine: InnoDB 170329 8:26:23 [ERROR] Aborting 170329 8:26:23 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete 170329 08:26:23 mysqld_safe mysqld from pid file /usr/local/mysql/var/104-250-159-170.static.gorillaservers.com.pid ended
解决办法：在my.cnf 把 innodb_buffer_pool_size 的值设置小点。
参考：
http://serverfault.com/questions/379714/unknown-unsupported-storage-engine-innodb-mysql-ubuntu
http://blog.csdn.net/psiitoy/article/details/40106735