我正在 Amazon EC2 实例上运行 Web 服务器，并使用 Amazon Linux AMI 作为我的实例操作系统（我认为是 CentOS 或类似的）。
无论如何，在过去的一个月左右，MySQL 出现了一些奇怪的问题。大约每周一次，MySQL 似乎会随机关闭，然后我会收到错误“无法通过套接字 mysql.sock 连接到本地 MySQL 服务器。”
我设法修复此错误的唯一方法是重新启动 EC2 实例，这意味着我几乎每周都要手动重新启动实例一次。我想知道为什么 MySQL 每周都会随机停止工作一次。
任何帮助将不胜感激。
内容/var/log/mysqld.log：
30414 20:03:45 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
130414 20:03:45 [Note] Plugin 'FEDERATED' is disabled.
130414 20:03:45 InnoDB: The InnoDB memory heap is disabled
130414 20:03:45 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130414 20:03:45 InnoDB: Compressed tables use zlib 1.2.5
130414 20:03:45 InnoDB: Using Linux native AIO
130414 20:03:45 InnoDB: Initializing buffer pool, size = 128.0M
130414 20:03:45 InnoDB: Completed initialization of buffer pool
InnoDB: The first specified data file ./ibdata1 did not exist:
InnoDB: a new database to be created!
130414 20:03:45 InnoDB: Setting file ./ibdata1 size to 10 MB
InnoDB: Database physically writes the file full: wait...
130414 20:03:46 InnoDB: Log file ./ib_logfile0 did not exist: new to be created
InnoDB: Setting log file ./ib_logfile0 size to 5 MB
InnoDB: Database physically writes the file full: wait...
130414 20:03:46 InnoDB: Log file ./ib_logfile1 did not exist: new to be created
InnoDB: Setting log file ./ib_logfile1 size to 5 MB
InnoDB: Database physically writes the file full: wait...
InnoDB: Doublewrite buffer not found: creating new
InnoDB: Doublewrite buffer created
InnoDB: 127 rollback segment(s) active.
InnoDB: Creating foreign key constraint system tables
InnoDB: Foreign key constraint system tables created
130414 20:03:47 InnoDB: Waiting for the background threads to start
130414 20:03:48 InnoDB: 5.5.30 started; log sequence number 0
130414 20:03:48 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
130414 20:03:48 [Note] - '0.0.0.0' resolves to '0.0.0.0';
130414 20:03:48 [Note] Server socket created on IP: '0.0.0.0'.
130414 20:03:48 [Note] Event Scheduler: Loaded 0 events
130414 20:03:48 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.30' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Server (GPL)
130519 22:55:03 [Note] /usr/libexec/mysqld: Normal shutdown
130519 22:55:03 [Note] Event Scheduler: Purging the queue. 0 events
130519 22:55:03 InnoDB: Starting shutdown...
130519 22:55:04 InnoDB: Shutdown completed; log sequence number 1595675
130519 22:55:04 [Note] /usr/libexec/mysqld: Shutdown complete
130519 22:55:04 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
130519 22:55:05 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
130519 22:55:05 [Note] Plugin 'FEDERATED' is disabled.
130519 22:55:05 InnoDB: The InnoDB memory heap is disabled
130519 22:55:05 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130519 22:55:05 InnoDB: Compressed tables use zlib 1.2.5
130519 22:55:05 InnoDB: Using Linux native AIO
130519 22:55:05 InnoDB: Initializing buffer pool, size = 128.0M
130519 22:55:05 InnoDB: Completed initialization of buffer pool
130519 22:55:05 InnoDB: highest supported file format is Barracuda.
130519 22:55:06 InnoDB: Waiting for the background threads to start
130519 22:55:07 InnoDB: 5.5.31 started; log sequence number 1595675
130519 22:55:07 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
130519 22:55:07 [Note] - '0.0.0.0' resolves to '0.0.0.0';
130519 22:55:07 [Note] Server socket created on IP: '0.0.0.0'.
130519 22:55:07 [Note] Event Scheduler: Loaded 0 events
130519 22:55:07 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.31' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Server (GPL)
130602 19:10:33 mysqld_safe Number of processes running now: 0
130602 19:10:33 mysqld_safe mysqld restarted
130602 19:10:33 [Note] Plugin 'FEDERATED' is disabled.
130602 19:10:33 InnoDB: The InnoDB memory heap is disabled
130602 19:10:33 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130602 19:10:33 InnoDB: Compressed tables use zlib 1.2.5
130602 19:10:33 InnoDB: Using Linux native AIO
130602 19:10:33 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
130602 19:10:33 InnoDB: Completed initialization of buffer pool
130602 19:10:33 InnoDB: Fatal error: cannot allocate memory for the buffer pool
130602 19:10:33 [ERROR] Plugin 'InnoDB' init function returned error.
130602 19:10:33 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
130602 19:10:33 [ERROR] Unknown/unsupported storage engine: InnoDB
130602 19:10:33 [ERROR] Aborting
130602 19:10:33 [Note] /usr/libexec/mysqld: Shutdown complete
130602 19:10:33 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
130602 19:15:23 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
130602 19:15:23 [Note] Plugin 'FEDERATED' is disabled.
130602 19:15:23 InnoDB: The InnoDB memory heap is disabled
130602 19:15:23 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130602 19:15:23 InnoDB: Compressed tables use zlib 1.2.5
130602 19:15:23 InnoDB: Using Linux native AIO
130602 19:15:23 InnoDB: Initializing buffer pool, size = 128.0M
130602 19:15:23 InnoDB: Completed initialization of buffer pool
130602 19:15:24 InnoDB: highest supported file format is Barracuda.
InnoDB: Log scan progressed past the checkpoint lsn 129807478
130602 19:15:24 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...
InnoDB: Doing recovery: scanned up to log sequence number 129809289
130602 19:15:24 InnoDB: Starting an apply batch of log records to the database...
InnoDB: Progress in percents: 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
InnoDB: Apply batch completed
130602 19:15:24 InnoDB: Waiting for the background threads to start
130602 19:15:25 InnoDB: 5.5.31 started; log sequence number 129809289
130602 19:15:25 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
130602 19:15:25 [Note] - '0.0.0.0' resolves to '0.0.0.0';
130602 19:15:25 [Note] Server socket created on IP: '0.0.0.0'.
130602 19:15:25 [Note] Event Scheduler: Loaded 0 events
130602 19:15:25 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.31' socket: '/var/lib/mysql/mysql.sock' port: 3306 MySQL Community Server (GPL)
130604 12:07:41 mysqld_safe Number of processes running now: 0
130604 12:07:41 mysqld_safe mysqld restarted
130604 12:07:41 [Note] Plugin 'FEDERATED' is disabled.
130604 12:07:41 InnoDB: The InnoDB memory heap is disabled
130604 12:07:41 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130604 12:07:41 InnoDB: Compressed tables use zlib 1.2.5
130604 12:07:41 InnoDB: Using Linux native AIO
130604 12:07:41 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
130604 12:07:41 InnoDB: Completed initialization of buffer pool
130604 12:07:41 InnoDB: Fatal error: cannot allocate memory for the buffer pool
130604 12:07:41 [ERROR] Plugin 'InnoDB' init function returned error.
130604 12:07:41 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
130604 12:07:41 [ERROR] Unknown/unsupported storage engine: InnoDB
130604 12:07:41 [ERROR] Aborting
130604 12:07:41 [Note] /usr/libexec/mysqld: Shutdown complete
130604 12:07:41 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
130604 12:10:46 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
130604 12:10:47 [Note] Plugin 'FEDERATED' is disabled.
130604 12:10:47 InnoDB: The InnoDB memory heap is disabled
130604 12:10:47 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130604 12:10:47 InnoDB: Compressed tables use zlib 1.2.5
130604 12:10:47 InnoDB: Using Linux native AIO
130604 12:10:47 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
130604 12:10:47 InnoDB: Completed initialization of buffer pool
130604 12:10:47 InnoDB: Fatal error: cannot allocate memory for the buffer pool
130604 12:10:47 [ERROR] Plugin 'InnoDB' init function returned error.
130604 12:10:47 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
130604 12:10:47 [ERROR] Unknown/unsupported storage engine: InnoDB
130604 12:10:47 [ERROR] Aborting
130604 12:10:47 [Note] /usr/libexec/mysqld: Shutdown complete
130604 12:10:47 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
130604 12:10:59 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
130604 12:10:59 [Note] Plugin 'FEDERATED' is disabled.
130604 12:10:59 InnoDB: The InnoDB memory heap is disabled
130604 12:10:59 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130604 12:10:59 InnoDB: Compressed tables use zlib 1.2.5
130604 12:10:59 InnoDB: Using Linux native AIO
130604 12:10:59 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
130604 12:10:59 InnoDB: Completed initialization of buffer pool
130604 12:10:59 InnoDB: Fatal error: cannot allocate memory for the buffer pool
130604 12:10:59 [ERROR] Plugin 'InnoDB' init function returned error.
130604 12:10:59 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
130604 12:10:59 [ERROR] Unknown/unsupported storage engine: InnoDB
130604 12:10:59 [ERROR] Aborting
答案1
检查 /var/lib/mysql/mysql.sock 的所有权和权限。收到此错误消息时，请尝试检查该文件是否存在。如果不存在，请创建它并重新启动服务以查看它是否有效。
我猜是你的虚拟机内存不足。我建议使用像 Nginx 这样的轻量级 Web 服务器，并禁用 MySQL 中所有不使用的后端。我知道 MariaDB 会消耗大量内存，因为它使用了很多后端。