我试图改变MySQL的datadir 。 当我尝试重新启动服务时，它挂起10分钟，然后重新启动失败。 以下是我用来更改目录的步骤：
drwxr-XR-X。 4 mysql mysql 4.0K 8月24日17:51 msqyl2
这给了我：
mysqld.service的作业失败，因为超时。 有关详细信息，请参阅“systemctl status mysqld.service”和“journalctl -xe”。
大约10分钟后处理start 。 如果我反转注释以便目录是默认目录，那么重新启动在<5秒内工作。
journalctl -xe带回：
Aug 24 18:35:17 uroot-ARTMO-myserver-1 systemd[1]: mysqld.service start-post operation timed out. Stopping. Aug 24 18:35:17 uroot-ARTMO-myserver-1 systemd[1]: Failed to start MySQL Community Server. -- Subject: Unit mysqld.service has failed -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit mysqld.service has failed. -- -- The result is failed. Aug 24 18:35:17 uroot-ARTMO-myserver-1 systemd[1]: Unit mysqld.service entered failed state. Aug 24 18:35:18 uroot-ARTMO-myserver-1 systemd[1]: mysqld.service failed. Aug 24 18:35:18 uroot-ARTMO-myserver-1 polkitd[1309]: Unregistered Authentication Agent for unix-process:22433:121785532 (system bus name :1.833, object path /org/freedesktop/PolicyKi Aug 24 18:35:18 uroot-ARTMO-myserver-1 systemd[1]: mysqld.service holdoff time over, scheduling restart. Aug 24 18:35:18 uroot-ARTMO-myserver-1 systemd[1]: Starting MySQL Community Server... -- Subject: Unit mysqld.service has begun start-up -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit mysqld.service has begun starting up. Aug 24 18:35:18 uroot-ARTMO-myserver-1 mysqld_safe[24090]: 160824 18:35:18 mysqld_safe Logging to '/var/log/mysqld.log'. Aug 24 18:35:18 uroot-ARTMO-myserver-1 mysqld_safe[24090]: 160824 18:35:18 mysqld_safe Starting mysqld daemon with databases from /srv/mysql2 Aug 24 18:35:18 uroot-ARTMO-myserver-1 mysqld_safe[24090]: 160824 18:35:18 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
systemctl status mysqld.service带回：
● mysqld.service - MySQL Community Server Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled) Active: activating (start-post) since Wed 2016-08-24 18:45:18 CEST; 8min ago Process: 26133 ExecStart=/usr/bin/mysqld_safe (code=exited, status=0/SUCCESS) Process: 26120 ExecStartPre=/usr/bin/mysql-systemd-start pre (code=exited, status=0/SUCCESS) Main PID: 26133 (code=exited, status=0/SUCCESS); : 26134 (mysql-systemd-s) CGroup: /system.slice/mysqld.service └─control ├─26134 /bin/bash /usr/bin/mysql-systemd-start post └─27942 sleep 1 Aug 24 18:45:18 uroot-ARTMO-myserver-1 systemd[1]: Starting MySQL Community Server... Aug 24 18:45:18 uroot-ARTMO-myserver-1 mysqld_safe[26133]: 160824 18:45:18 mysqld_safe Logging to '/var/log/mysqld.log'. Aug 24 18:45:18 uroot-ARTMO-myserver-1 mysqld_safe[26133]: 160824 18:45:18 mysqld_safe Starting mysqld daemon with databases from /srv/mysql2
默认的dir /var/lib/mysql的权限是：
drwx ——。 2 mysql mysql 4.0K 8月18日21:32 mysql
mysqld.log有：
160824 18:35:18 mysqld_safe Starting mysqld daemon with databases from /srv/mysql2 2016-08-24 18:35:18 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2016-08-24 18:35:18 0 [Note] /usr/sbin/mysqld (mysqld 5.6.32) starting as process 24253 ... 2016-08-24 18:35:18 24253 [Warning] Can't create test file /srv/mysql2/uroot-ARTMO-myserver-1.lower-test 2016-08-24 18:35:18 24253 [Warning] Can't create test file /srv/mysql2/uroot-ARTMO-myserver-1.lower-test 2016-08-24 18:35:18 24253 [Warning] Buffered warning: Changed limits: max_open_files: 1024 (requested 5000) 2016-08-24 18:35:18 24253 [Warning] Buffered warning: Changed limits: table_open_cache: 431 (requested 2000) 2016-08-24 18:35:18 24253 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13 - Permission denied) 2016-08-24 18:35:18 24253 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 2016-08-24 18:35:18 24253 [Note] InnoDB: Using atomics to ref count buffer pool pages 2016-08-24 18:35:18 24253 [Note] InnoDB: The InnoDB memory heap is disabled 2016-08-24 18:35:18 24253 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2016-08-24 18:35:18 24253 [Note] InnoDB: Memory barrier is not used 2016-08-24 18:35:18 24253 [Note] InnoDB: Compressed tables use zlib 1.2.3 2016-08-24 18:35:18 24253 [Note] InnoDB: Using Linux native AIO 2016-08-24 18:35:18 24253 [Note] InnoDB: Using CPU crc32 instructions 2016-08-24 18:35:18 24253 [Note] InnoDB: Initializing buffer pool, size = 128.0M 2016-08-24 18:35:18 24253 [Note] InnoDB: Completed initialization of buffer pool 2016-08-24 18:35:18 7f32872e8740 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. 2016-08-24 18:35:18 24253 [ERROR] InnoDB: os_file_get_status() failed on './ibdata1'. Can't determine file permissions 2016-08-24 18:35:18 24253 [ERROR] InnoDB: The system tablespace must be writable! 2016-08-24 18:35:18 24253 [ERROR] Plugin 'InnoDB' init function returned error. 2016-08-24 18:35:18 24253 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 2016-08-24 18:35:18 24253 [ERROR] Unknown/unsupported storage engine: InnoDB 2016-08-24 18:35:18 24253 [ERROR] Aborting 2016-08-24 18:35:18 24253 [Note] Binlog end 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'partition' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'PERFORMANCE_SCHEMA' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_DATAFILES' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_TABLESPACES' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN_COLS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_FIELDS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_COLUMNS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_INDEXES' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_TABLESTATS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_SYS_TABLES' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_INDEX_TABLE' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_INDEX_CACHE' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_CONFIG' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_BEING_DELETED' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_DELETED' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_FT_DEFAULT_STOPWORD' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_METRICS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_BUFFER_POOL_STATS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE_LRU' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX_RESET' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMPMEM_RESET' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMPMEM' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMP_RESET' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_CMP' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_LOCK_WAITS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_LOCKS' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'INNODB_TRX' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'BLACKHOLE' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'ARCHIVE' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'MRG_MYISAM' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'MyISAM' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'MEMORY' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'CSV' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'sha256_password' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'mysql_old_password' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'mysql_native_password' 2016-08-24 18:35:18 24253 [Note] Shutting down plugin 'binlog' 2016-08-24 18:35:18 24253 [Note] /usr/sbin/mysqld: Shutdown complete 160824 18:35:18 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
很多时候，这是因为像apparmor的东西。 检查/etc/如果有apparmor，selinux，或任何configuration文件，限制mysql到/var/lib/mysql 。
如果你在问题中发布的命令是正确的，那么你有一个错字。
sudo cp -R -p /var/lib/mysql /srv/msqyl2 ls -lha /srv/mysql2 drwxr-xr-x. 4 mysql mysql 4.0K Aug 24 17:51 msqyl2 Add a new line with same directive but new location, `datadir=/srv/mysql2`
mysql2不是msqyl2