无法为缓冲池分配内存

Question

在启动Mysql时，我们面临着一个非常严重的问题。我们使用的是数字海洋。

Droplet
RAM = 8GB 
CPU = 4Core
Mysql Version = 5.6

My.cnf

    [mysql]
    # CLIENT #
    port                           = 3306
    socket                         = /var/lib/mysql/mysql.sock

    [mysqld]
    max_connections                = 300
    open_files_limit               = 1024000
    #interactive_timeout           = 30
    #wait_timeout              = 30
    # GENERAL #
    user                           = mysql
    default-storage-engine         = InnoDB
    socket                         = /var/lib/mysql/mysql.sock
    pid-file                       = /var/lib/mysql/mysql.pid

    # MyISAM #
    key-buffer-size                = 64M
    myisam-recover                 = FORCE,BACKUP

    # SAFETY #
    max-allowed-packet             = 16M
    max-connect-errors             = 1000000
    skip-name-resolve
    sysdate-is-now                 = 1
    innodb                         = FORCE

    # DATA STORAGE #
    datadir                        = /var/lib/mysql/

    # BINARY LOGGING #
    log-bin                        = /var/lib/mysql/mysql-bin
    expire_logs_days               = 10
    #expire-logs-days              = 14
    sync_binlog                    = 1

    # CACHES AND LIMITS #
    tmp-table-size                 = 500M
    max-heap-table-size            = 500M
    query-cache-type               = 0
    query-cache-size               = 64M
    #max-connections                = 300
    thread-cache-size              = 50
    #open_files_limit               = 65535
    table-definition-cache         = 1024M
    table_open_cache               = 600

    # INNODB #
    innodb-flush-method            = O_DIRECT
    innodb-log-files-in-group      = 2
    innodb-log-file-size           = 64M
    innodb-flush-log-at-trx-commit = 1
    innodb-file-per-table          = 1
    innodb-buffer-pool-size        = 12000M
    innodb-buffer-pool-instances   = 1
    join_buffer_size               = 6M

    # LOGGING #
    log-error                      = /var/lib/mysql/mysql-error.log
    log-queries-not-using-indexes  = 1
    slow-query-log                 = 1
    slow-query-log-file            = /var/lib/mysql/mysql-slow.log
    long-query-time            = 5
    log-queries-not-using-indexes

我们可以毫无错误地启动Mysql。

但是当我们将现有的液滴大小从8 8Gb内存和4CPU调整到16 8Gb和8CPU，并且没有在my.cnf中做任何更改，但无法启动MYSQL。

在启动MySql期间，它会消耗所有内存、16 5GB内存和5 5GB交换空间。

它会显示错误。

160910 18:15:03 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql/
    2016-09-10 18:15:32 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
    2016-09-10 18:15:32 0 [Note] /usr/sbin/mysqld (mysqld 5.6.31-log) starting as process 14643 ...
    2016-09-10 18:15:32 14643 [Warning] Buffered warning: option 'table_definition_cache': unsigned value 1073741824 adjusted to 524288

    2016-09-10 18:15:32 14643 [Warning] Buffered warning: Could not increase number of max_open_files to more than 1024 (request: 1024000)

2016-09-10 18:15:32 14643 [Warning] Buffered warning: Changed limits: max_connections: 214 (requested 300)

2016-09-10 18:15:32 14643 [Warning] Buffered warning: Changed limits: table_open_cache: 400 (requested 600)

2016-09-10 18:15:32 14643 [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.
2016-09-10 18:15:32 14643 [Note] Plugin 'FEDERATED' is disabled.
2016-09-10 18:15:32 14643 [Warning] The option innodb (skip-innodb) is deprecated and will be removed in a future release
2016-09-10 18:15:32 14643 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-09-10 18:15:32 14643 [Note] InnoDB: The InnoDB memory heap is disabled
2016-09-10 18:15:32 14643 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-09-10 18:15:32 14643 [Note] InnoDB: Memory barrier is not used
2016-09-10 18:15:32 14643 [Note] InnoDB: Compressed tables use zlib 1.2.3
2016-09-10 18:15:32 14643 [Note] InnoDB: Using Linux native AIO
2016-09-10 18:15:32 14643 [Note] InnoDB: Using CPU crc32 instructions
2016-09-10 18:15:32 14643 [Note] InnoDB: Initializing buffer pool, size = 7.8G
InnoDB: mmap(8585216000 bytes) failed; errno 12
2016-09-10 18:15:32 14643 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
2016-09-10 18:15:32 14643 [ERROR] Plugin 'InnoDB' init function returned error.
2016-09-10 18:15:32 14643 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-09-10 18:15:32 14643 [ERROR] Failed to initialize plugins.
2016-09-10 18:15:32 14643 [ERROR] Aborting
2016-09-10 18:15:32 14643 [Note] Binlog end
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'partition'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'PERFORMANCE_SCHEMA'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_DATAFILES'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_TABLESPACES'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN_COLS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_FIELDS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_COLUMNS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_INDEXES'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_TABLESTATS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_SYS_TABLES'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_INDEX_TABLE'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_INDEX_CACHE'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_CONFIG'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_BEING_DELETED'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_DELETED'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_FT_DEFAULT_STOPWORD'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_METRICS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_BUFFER_POOL_STATS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE_LRU'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX_RESET'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMPMEM_RESET'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMPMEM'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMP_RESET'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_CMP'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_LOCK_WAITS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_LOCKS'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'INNODB_TRX'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'BLACKHOLE'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'ARCHIVE'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'MRG_MYISAM'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'MyISAM'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'MEMORY'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'CSV'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'sha256_password'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'mysql_old_password'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'mysql_native_password'
2016-09-10 18:15:32 14643 [Note] Shutting down plugin 'binlog'
2016-09-10 18:15:32 14643 [Note] /usr/sbin/mysqld: Shutdown complete
160910 18:15:33 mysqld_safe mysqld from pid file /var/lib/mysql/mysql.pid ended

我不能理解为什么mysql在任何设置下都不能启动。

我有5 5GB的交换内存。

根据我的说法，我认为这是DigitalOcean的问题，原因是相同的配置在8 8GB内存上工作，但它在16 8GB内存上不工作，但他们声称在16 8GB液滴上没有问题。

在启动MySQL之前说免费的-m

 total        used        free      shared  buff/cache   available
Mem:          16047         122       15843           1          81       15792
Swap:          2047          38        2009
Total:        18095         160       17853

取消命名-a

3.10.0-327.10.1.el7.x86_64 #1 SMP Tue Feb 16 17:03:50 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

另外，我想提到的是，我们只安装了mysql，没有安装其他服务。

请帮助解决这个问题。

谢谢

Answer 1

问题是Apache服务器不是mysql，实际上您需要将innodb-buffer-pool-size减小到300M左右

你有1.2Gb+内存被mysql进程使用，当Apache需要更多的资源时，内核将从服务中清除内存，这意味着停止mysql而不是使服务器崩溃。

我还会添加一个CRON来检查数据库的状态，如果你不想更改为nginx或lighttp，可以重新启动它。