服务器同时访问ip不到1000，就占满了cpu和内存

服务器配置：
CPU： 1核    内存： 2048 MB
2Mbps
CentOS 6.5 64位
Apache2.4
Mysql：5.6




最近网站经常出现数据库链接不上，特别是晚上，很郁闷，晚上又不知道，每次都是第二天才知道然后重启服务器，网站才能访问。
看后台又没有人攻击，也扫描木马什么的，也没有。
然后用软件看，cpu老是异常。
就测试了下，1000ip不到访问一个页面，就瞬间让整个服务器的cpu爆满，内存也站了1.3-1.5G左右。
其中数据库就占用30-50%左右。


不知道是数据库有问题还是什么？


平时正常情况下服务器cpu占用还不到5%，数据库占用cpu更少了。


就是并发一多，数据库就挂了。



我把之前的数据库错误日志删了，之前的太多了，也不数据数据库这块。
刚才我自己用代理ip访问网站，然后网站就打不开，数据库停止运行了。
下面是我刚才测试得到的数据库日志，还望各位帮忙看看。

161002 15:31:43 mysqld_safe Number of processes running now: 0
161002 15:31:43 mysqld_safe mysqld restarted
2016-10-02 15:31:44 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-10-02 15:31:45 14693 [Note] Plugin 'FEDERATED' is disabled.
2016-10-02 15:31:45 14693 [Note] InnoDB: Using atomics to ref count buffer pool pages
2016-10-02 15:31:45 14693 [Note] InnoDB: The InnoDB memory heap is disabled
2016-10-02 15:31:45 14693 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-10-02 15:31:45 14693 [Note] InnoDB: Memory barrier is not used
2016-10-02 15:31:45 14693 [Note] InnoDB: Compressed tables use zlib 1.2.3
2016-10-02 15:31:45 14693 [Note] InnoDB: Using Linux native AIO
2016-10-02 15:31:45 14693 [Note] InnoDB: Using CPU crc32 instructions
2016-10-02 15:31:45 14693 [Note] InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137363456 bytes) failed; errno 12
2016-10-02 15:31:45 14693 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
2016-10-02 15:31:45 14693 [ERROR] Plugin 'InnoDB' init function returned error.
2016-10-02 15:31:45 14693 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2016-10-02 15:31:45 14693 [ERROR] Unknown/unsupported storage engine: InnoDB
2016-10-02 15:31:45 14693 [ERROR] Aborting

2016-10-02 15:31:45 14693 [Note] Binlog end
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'partition'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'PERFORMANCE_SCHEMA'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'BLACKHOLE'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_DATAFILES'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_TABLESPACES'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN_COLS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_FIELDS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_COLUMNS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_INDEXES'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_TABLESTATS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_SYS_TABLES'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_INDEX_TABLE'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_INDEX_CACHE'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_CONFIG'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_BEING_DELETED'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_DELETED'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_FT_DEFAULT_STOPWORD'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_METRICS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_BUFFER_POOL_STATS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE_LRU'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX_RESET'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMPMEM_RESET'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMPMEM'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMP_RESET'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_CMP'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_LOCK_WAITS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_LOCKS'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'INNODB_TRX'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'ARCHIVE'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'MyISAM'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'CSV'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'MRG_MYISAM'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'MEMORY'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'sha256_password'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'mysql_old_password'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'mysql_native_password'
2016-10-02 15:31:45 14693 [Note] Shutting down plugin 'binlog'
2016-10-02 15:31:45 14693 [Note] /alidata/server/mysql/bin/mysqld: Shutdown complete

161002 15:31:45 mysqld_safe mysqld from pid file /alidata/server/mysql/data/AY140716132949Z.pid ended