my vps is running normally but mysql suddenly stopped and i can’t restart it
please help me fix this problem 
[root@vps ~]# service mysql start
Starting MySQL (Percona Server). ERROR! The server quit without updating PID file (/var/lib/mysql/vps.pid).
there are many warnings in my log file
[Warning] IP address ‘xxx.xxx.xxx.xxx’ could not be resolved: Name or service not known
what are they ?
here is my log file
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140409 22:00:27 mysqld_safe mysqld from pid file /var/lib/mysql/vps.vanmau.com.pid ended
140409 22:00:50 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140409 22:00:50 [Note] Plugin ‘FEDERATED’ is disabled.
140409 22:00:50 InnoDB: The InnoDB memory heap is disabled
140409 22:00:50 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140409 22:00:50 InnoDB: Compressed tables use zlib 1.2.3
140409 22:00:50 InnoDB: Using Linux native AIO
140409 22:00:50 InnoDB: Initializing buffer pool, size = 128.0M
140409 22:00:50 InnoDB: Completed initialization of buffer pool
140409 22:00:50 InnoDB: highest supported file format is Barracuda.
140409 22:00:51 InnoDB: Waiting for the background threads to start
140409 22:00:52 Percona XtraDB (http://www.percona.com) 5.5.36-34.2-34.2 started; log sequence number 258186544
140409 22:00:54 [Note] Event Scheduler: Loaded 0 events
140409 22:00:54 [Note] /usr/sbin/mysqld: ready for connections.
Version: ‘5.5.36-34.2’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Percona Server (GPL), Release rel34.2, Revision 648
140416 21:49:01 [Warning] IP address ‘113.17.173.12’ could not be resolved: Name or service not known
140418 0:38:31 [Warning] IP address ‘112.253.1.9’ could not be resolved: Name or service not known
140418 0:40:37 [Warning] IP address ‘112.253.1.11’ could not be resolved: Name or service not known
140418 1:22:01 [Warning] IP address ‘108.186.4.216’ could not be resolved: Name or service not known
140418 1:22:01 [Warning] IP address ‘108.186.4.216’ could not be resolved: Name or service not known
140419 0:44:05 [Warning] IP address ‘112.124.19.107’ could not be resolved: Name or service not known
140419 03:22:53 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140419 3:22:53 [Note] Plugin ‘FEDERATED’ is disabled.
140419 3:22:53 InnoDB: The InnoDB memory heap is disabled
140419 3:22:53 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140419 3:22:53 InnoDB: Compressed tables use zlib 1.2.3
140419 3:22:53 InnoDB: Using Linux native AIO
140419 3:22:53 InnoDB: Initializing buffer pool, size = 128.0M
140419 3:22:53 InnoDB: Completed initialization of buffer pool
140419 3:22:53 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
140419 3:22:53 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…
140419 3:23:01 InnoDB: Waiting for the background threads to start
140419 3:23:02 Percona XtraDB (http://www.percona.com) 5.5.36-34.2-34.2 started; log sequence number 325385349
140419 3:23:02 [Note] Event Scheduler: Loaded 0 events
140419 3:23:02 [Note] /usr/sbin/mysqld: ready for connections.
Version: ‘5.5.36-34.2’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Percona Server (GPL), Release rel34.2, Revision 648
140420 2:15:37 [Warning] IP address ‘113.17.173.12’ could not be resolved: Name or service not known
140420 17:12:32 [Warning] IP address ‘112.124.19.107’ could not be resolved: Name or service not known
140421 3:02:32 [Warning] IP address ‘115.238.101.202’ could not be resolved: Name or service not known
140421 3:02:33 [Warning] IP address ‘115.238.101.202’ could not be resolved: Name or service not known
140421 18:40:56 [Warning] IP address ‘117.21.227.30’ could not be resolved: Name or service not known
140424 10:03:08 [Warning] IP address ‘203.166.160.158’ could not be resolved: Name or service not known
140426 6:10:29 [Warning] IP address ‘61.183.41.74’ could not be resolved: Name or service not known
140427 11:03:48 [Warning] IP address ‘180.225.203.220’ could not be resolved: Name or service not known
140428 2:27:31 [Warning] IP address ‘175.102.4.196’ could not be resolved: Name or service not known
140429 2:21:01 [Warning] IP address ‘125.76.230.172’ could not be resolved: Name or service not known
140429 18:50:56 [Warning] IP address ‘124.232.163.29’ could not be resolved: Name or service not known
140430 23:43:33 [Warning] IP address ‘211.157.162.43’ could not be resolved: Name or service not known
140501 11:58:25 [Warning] IP address ‘61.147.103.160’ could not be resolved: Name or service not known
140504 7:31:46 [Warning] IP address ‘192.161.51.191’ has been resolved to the host name ‘192.161.51.191.static.quadranet.com’, which resembles IPv4-address itself.
140504 15:00:50 [Warning] IP address ‘175.42.84.27’ could not be resolved: Name or service not known
140505 16:13:57 [Warning] IP address ‘116.255.162.234’ could not be resolved: Temporary failure in name resolution
140505 16:17:40 [Warning] IP address ‘116.255.162.234’ could not be resolved: Temporary failure in name resolution
140507 19:48:47 [Warning] IP address ‘110.45.211.141’ could not be resolved: Name or service not known
140509 11:27:16 [Warning] IP address ‘94.102.53.136’ could not be resolved: Name or service not known
140510 14:04:06 [Warning] IP address ‘125.46.54.212’ could not be resolved: Temporary failure in name resolution
140516 17:09:42 [Warning] IP address ‘59.53.168.136’ has been resolved to the host name ‘136.168.53.59.broad.nc.jx.dynamic.163data.com.cn’, which resembles IPv4-address itself.
140518 5:00:41 [Warning] IP address ‘42.117.1.145’ could not be resolved: Name or service not known
140518 5:26:07 [Note] /usr/sbin/mysqld: Normal shutdown
140518 5:26:07 [Note] Event Scheduler: Purging the queue. 0 events
140518 5:26:07 InnoDB: Starting shutdown…
140518 5:26:08 InnoDB: Waiting for 4 pages to be flushed
140518 5:26:12 InnoDB: Shutdown completed; log sequence number 884126277
140518 5:26:12 [Note] /usr/sbin/mysqld: Shutdown complete
140518 05:26:12 mysqld_safe mysqld from pid file /var/lib/mysql/vps.vanmau.com.pid ended
140518 05:26:25 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140518 5:26:25 [Note] Plugin ‘FEDERATED’ is disabled.
140518 5:26:25 InnoDB: The InnoDB memory heap is disabled
140518 5:26:25 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140518 5:26:25 InnoDB: Compressed tables use zlib 1.2.3
140518 5:26:25 InnoDB: Using Linux native AIO
140518 5:26:25 InnoDB: Initializing buffer pool, size = 128.0M
140518 5:26:25 InnoDB: Completed initialization of buffer pool
140518 5:26:25 InnoDB: highest supported file format is Barracuda.
140518 5:26:25 InnoDB: Waiting for the background threads to start
140518 5:26:26 Percona XtraDB (http://www.percona.com) 5.5.36-34.2-34.2 started; log sequence number 884126277
140518 5:26:27 [Note] Event Scheduler: Loaded 0 events
140518 5:26:27 [Note] /usr/sbin/mysqld: ready for connections.
Version: ‘5.5.36-34.2’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Percona Server (GPL), Release rel34.2, Revision 648
140519 17:34:48 [Warning] IP address ‘122.224.11.40’ could not be resolved: Name or service not known
140521 2:16:05 [Warning] IP address ‘61.147.110.72’ could not be resolved: Name or service not known
140521 12:47:18 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
140521 12:47:19 [Note] Plugin ‘FEDERATED’ is disabled.
140521 12:47:19 InnoDB: The InnoDB memory heap is disabled
140521 12:47:19 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140521 12:47:19 InnoDB: Compressed tables use zlib 1.2.3
140521 12:47:19 InnoDB: Using Linux native AIO
140521 12:47:19 InnoDB: Warning: io_setup() failed with EAGAIN. Will make 5 attempts before giving up.
InnoDB: Warning: io_setup() attempt 1 failed.
InnoDB: Warning: io_setup() attempt 2 failed.
InnoDB: Warning: io_setup() attempt 3 failed.
InnoDB: Warning: io_setup() attempt 4 failed.
InnoDB: Warning: io_setup() attempt 5 failed.
140521 12:47:22 InnoDB: Error: io_setup() failed with EAGAIN after 5 attempts.
InnoDB: You can disable Linux Native AIO by setting innodb_use_native_aio = 0 in my.cnf
140521 12:47:22 InnoDB: Fatal error: cannot initialize AIO sub-system
140521 12:47:22 [ERROR] Plugin ‘InnoDB’ init function returned error.
140521 12:47:22 [ERROR] Plugin ‘InnoDB’ registration as a STORAGE ENGINE failed.
140521 12:47:22 [ERROR] Unknown/unsupported storage engine: InnoDB
140521 12:47:22 [ERROR] Aborting
140521 12:47:22 [Note] /usr/sbin/mysqld: Shutdown complete
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