mysql启动失败Starting MySQL.The server quit without updating PID file ([失败]ysqllnmp.pid) 一开始以为没有给/data/mysql的文件夹写入的权限，后来干脆给777的权限，但是启动还是报错，最后查看日志 InnoDB: the log sequence number in the ib_logfiles! 161126 17:30:58 InnoDB: Database was not shut down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files… InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer… 161126 17:30:58 InnoDB: Waiting for the background threads to start 161126 17:30:59 InnoDB: 1.1.8 started; log sequence number 1595916 161126 17:30:59 [Note] Server hostname (bind-address): ‘0.0.0.0’; port: 3306 161126 17:30:59 [Note] - ‘0.0.0.0’ resolves to ‘0.0.0.0’; 161126 17:30:59 [Note] Server socket created on IP: ‘0.0.0.0’. 161126 17:30:59 [ERROR] /usr/local/mysql/bin/mysqld: Can’t create/write to file ‘/usr/local/mysql/data/lnmp.pid’ (Errcode: 13) 161126 17:30:59 [ERROR] Can’t start server: can’t create PID file: Permission denied 161126 17:30:59 mysqld_safe mysqld from pid file /usr/local/mysql/data/lnmp.pid ended 161126 17:38:50 mysqld_safe Starting mysqld daemon with databases from /data/mysql 161126 17:38:50 InnoDB: The InnoDB memory heap is disabled 161126 17:38:50 InnoDB: Mutexes and rw_locks use GCC atomic builtins 161126 17:38:50 InnoDB: Compressed tables use zlib 1.2.3 161126 17:38:50 InnoDB: Initializing buffer pool, size = 128.0M 161126 17:38:50 InnoDB: Completed initialization of buffer pool InnoDB: Error: log file ./ib_logfile0 is of different size 0 10485760 bytes InnoDB: than specified in the .cnf file 0 5242880 bytes! 161126 17:38:50 [ERROR] Plugin ‘InnoDB’ init function returned error. 161126 17:38:50 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed. 161126 17:38:50 [ERROR] Unknown/unsupported storage engine: InnoDB 161126 17:38:50 [ERROR] Aborting
161126 17:38:50 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete
161126 17:38:50 mysqld_safe mysqld from pid file /data/mysql/lnmp.pid ende 并不是说没有写入的权限，，后来讲/data/mysql中的 全部删除，再启动mysql就可以了
引起这个问题的还有一个是内存不足，需要查看下/etc/my.cnf中的[mysqld]的配置
原先 设置的log_file的大小是1G，buffer_pool_size 是4G，现在换成小点的，就可以了
