我已經啟動並運行了我的應用程序，並在 Linode 中的 ubuntu VPS 上使用 Rails 和 mysql。
這是mysql的版本：
mysql Ver 14.14 Distrib 5.5.35, for debian-linux-gnu (x86_64) using readline 6.2
通常一切都運作正常，除了有時當我打開新的 Rails 控制台時，我會收到以下錯誤：
/var/www/app/shared/bundle/ruby/2.0.0/gems/mysql2-0.3.14/lib/mysql2/client.rb:67:in `connect': Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) (Mysql2::Error)
from /var/www/app/shared/bundle/ruby/2.0.0/gems/mysql2-0.3.14/lib/mysql2/client.rb:67:in `initialize'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /home/user/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /var/www/app/shared/bundle/ruby/2.0.0/gems/activerecord-3.2.16/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /home/user/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
並且所有進入控制台的嘗試都失敗了。為什麼應用程式仍然運作良好並且仍在使用資料庫。
如果我在外殼中這樣做：
$ sudo /etc/init.d/mysql status
* MySQL is stopped.
$ sudo /etc/init.d/mysql stop
* Stopping MySQL database server mysqld ... [ OK ]
$ sudo /etc/init.d/mysql start
* Starting MySQL database server mysqld ... [fail]
但該應用程式一直運作良好。
/var/log/mysql/error.log在這三個命令之前是空的，在它們之後我讀到：
140510 19:14:32 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140510 19:14:32 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. Please use the full name instead.
140510 19:14:32 [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.
140510 19:14:32 [Note] Plugin 'FEDERATED' is disabled.
140510 19:14:32 InnoDB: The InnoDB memory heap is disabled
140510 19:14:32 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140510 19:14:32 InnoDB: Compressed tables use zlib 1.2.8
140510 19:14:32 InnoDB: Using Linux native AIO
140510 19:14:32 InnoDB: Initializing buffer pool, size = 128.0M
140510 19:14:32 InnoDB: Completed initialization of buffer pool
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
140510 19:14:32 InnoDB: Retrying to lock the first data file
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
..... several thousands of these lines...
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
140510 19:16:12 InnoDB: Unable to open the first data file
InnoDB: Error in opening ./ibdata1
140510 19:16:12 InnoDB: Operating system error number 11 in a file operation.
InnoDB: Error number 11 means 'Resource temporarily unavailable'.
InnoDB: Some operating system error numbers are described at
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/operating-system-error-codes.html
140510 19:16:12 InnoDB: Could not open or create data files.
140510 19:16:12 InnoDB: If you tried to add new data files, and it failed here,
140510 19:16:12 InnoDB: you should now edit innodb_data_file_path in my.cnf back
140510 19:16:12 InnoDB: to what it was, and remove the new ibdata files InnoDB created
140510 19:16:12 InnoDB: in this failed attempt. InnoDB only wrote those files full of
140510 19:16:12 InnoDB: zeros, but did not yet use them in any way. But be careful: do not
140510 19:16:12 InnoDB: remove old data files which contain your precious data!
140510 19:16:12 [ERROR] Plugin 'InnoDB' init function returned error.
140510 19:16:12 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140510 19:16:12 [ERROR] Unknown/unsupported storage engine: InnoDB
140510 19:16:12 [ERROR] Aborting
140510 19:16:12 [Note] /usr/sbin/mysqld: Shutdown complete
140510 19:16:12 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
只有重新啟動 VPS 似乎才能解決該問題，該問題在一兩次控制台連接後又出現了。
我認為關閉 Mysql 並init.d不會關閉它，要停止它我需要kill它，然後它會自動重新生成。
$ ps -ef | grep mysq[l]
mysql 31063 1 0 May19 ? 00:00:34 /usr/sbin/mysqld
$ sudo /etc/init.d/mysql stop
* Stopping MySQL database server mysqld [ OK ]
$ ps -ef | grep mysq[l]
mysql 31063 1 0 May19 ? 00:00:34 /usr/sbin/mysqld
$ sudo kill -9 31063
$ ps -ef | grep mysq[l]
mysql 6052 1 3 09:23 ? 00:00:00 /usr/sbin/mysqld
$
有什麼線索嗎？
答案1
這可能是因為mysql在啟動時無法啟動。
試試這個補救措施
/etc/init.d/mysqld 重新啟動
或者試試這個
從 /etc/my.cnf 檔案中刪除 basedir 屬性
為什麼？
basedir指令指示MySQL在哪裡找到它運行所需的所有內容：二進位、庫、資料等。內容。
對於透過 RPM 進行的典型安裝，不需要也不應該使用此指令。有關該指令的更詳盡描述，請參閱 MySQL 手冊。
筆記
事實上，由於記憶體問題，我也曾經遇到過這個問題。也嘗試檢查可用記憶體。