mysql启动失败，但没有error信息，请问如何解决？

Question

服务器环境：centos 6.4
启动代码：

# service mysqld start
Starting MySQL... ERROR! The server quit without updating PID file (/mnt/data/mysql/mysql.pid).

检查日志文件，也没有error：

131026 11:25:45 mysqld_safe Starting mysqld daemon with databases from /mnt/data/mysql
2013-10-26 11:25:46 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2013-10-26 11:25:46 13682 [Note] Plugin 'FEDERATED' is disabled.
2013-10-26 11:25:47 7feddd850720 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
2013-10-26 11:25:47 13682 [Note] InnoDB: The InnoDB memory heap is disabled
2013-10-26 11:25:47 13682 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2013-10-26 11:25:47 13682 [Note] InnoDB: Compressed tables use zlib 1.2.3
2013-10-26 11:25:47 13682 [Note] InnoDB: CPU does not support crc32 instructions
2013-10-26 11:25:47 13682 [Note] InnoDB: Using Linux native AIO
2013-10-26 11:25:47 13682 [Note] InnoDB: Initializing buffer pool, size = 10.0M
2013-10-26 11:25:47 13682 [Note] InnoDB: Completed initialization of buffer pool
131026 11:25:47 mysqld_safe mysqld from pid file /mnt/data/mysql/mysql.pid ended

检查目录权限：

# ls -l /mnt/data/
总用量 656020
drwxr-xr-x 7 mysql mysql      4096 10月 26 11:24 mysql

Answer 1

1. Please give the time relationship between the startup failure and the displayed log;
2. Please check the general logs under /var/log, such as messages, daemon.log, etc.;
3. Your server startup script seems to have been written or modified by yourself. Can you post it?

Answer 2

ls -lZ checks the SELinux permissions of mysql datadir

If it is a SELinux permission problem, you can use the following method to restore it. Assume that your datadir is /var/lib/mysql:

semanage fcontext -a -t mysqld_db_t "/var/lib/mysql(/.*)?"
restorecon -Rv /var/lib/mysql

Answer 3

I have encountered this problem several times. I'll write down what I did, but it may not necessarily be useful to you.

1. Check whether the datadir, pid-file, and stocket paths in the /etc/my.cnf configuration are correct
2. Check the permissions of mysql on the pid and socket directories
3. If it doesn’t work, just put the pid and sock files in the /tmp directory

I don’t know if it will be useful to you

Answer 4

cat /var/log/messages

It means there is not enough memory.
top check which programs occupy the memory,
or /etc/my.cnf and adjust the buffer pool
or sync && echo 1 > /proc/sys/vm/drop_caches Release memory