linux下Mysql启动问题

启动MySQL折腾近一下午

1、开始

[root@letfly ~]# service mysqld start
Redirecting to /bin/systemctl start  mysqld.service

Job failed. See system logs and 'systemctl status' for details.

[root@letfly ~]# cd /var/log/

[root@letfly log]# more mysqld.log
140812 16:11:56 mysqld_safe Starting mysqld daemon with databases from /var/li
b/mysql
140812 16:11:56 [Note] Plugin 'FEDERATED' is disabled.
140812 16:11:56 InnoDB: The InnoDB memory heap is disabled
140812 16:11:56 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140812 16:11:56 InnoDB: Compressed tables use zlib 1.2.5
140812 16:11:56 InnoDB: Using Linux native AIO
140812 16:11:56 InnoDB: Initializing buffer pool, size = 128.0M
140812 16:11:56 InnoDB: Completed initialization of buffer pool
140812 16:11:56 InnoDB: highest supported file format is Barracuda.
140812 16:11:56  InnoDB: Waiting for the background threads to start
140812 16:11:57 [ERROR] Do you already have another mysqld server running on port: 3306 ?

查看3306端口

[root@letfly ~]# netstat -tunlp | grep :3306

没结果

折腾了一段时间，果断yum remove mysql

2、接着

[root@letfly ~]# yum install mysql

[root@letfly ~]# yum install mysql-devel

[root@letfly ~]# yum install mysql-server

接着启动MySQL：

[root@letfly ~]# clear
[root@letfly ~]# service mysqld start
Redirecting to /bin/systemctl start  mysqld.service
Job failed. See system logs and 'systemctl status' for details.

仍不行，查看日志，如下：

[root@letfly ~]# cd /var/log/
[root@letfly log]# more mysqld.log
140812 16:11:56 mysqld_safe Starting mysqld daemon with databases from /var/li
b/mysql
140812 16:11:56 [Note] Plugin 'FEDERATED' is disabled.
140812 16:11:56 InnoDB: The InnoDB memory heap is disabled
140812 16:11:56 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140812 16:11:56 InnoDB: Compressed tables use zlib 1.2.5
140812 16:11:56 InnoDB: Using Linux native AIO
140812 16:11:56 InnoDB: Initializing buffer pool, size = 128.0M
140812 16:11:56 InnoDB: Completed initialization of buffer pool
140812 16:11:56 InnoDB: highest supported file format is Barracuda.
140812 16:11:56  InnoDB: Waiting for the background threads to start
140812 16:11:57 InnoDB: 1.1.8 started; log sequence number 1595675
140812 16:11:57 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
140812 16:11:57 [Note]   - '0.0.0.0' resolves to '0.0.0.0';
140812 16:11:57 [Note] Server socket created on IP: '0.0.0.0'.
140812 16:11:57 [ERROR] Can't start server : Bind on unix socket: No such file
 or directory
140812 16:11:57 [ERROR] Do you already have another mysqld server running on s
ocket: /opt/lampp/var/mysql/mysql.sock ?

原来是socket问题

[root@letfly mysql]# find / -name 'my.cnf'
/etc/my.cnf

修改my.cnf里的

datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock（你先有的mysql位置）

[root@letfly mysql]# service mysqld start
Redirecting to /bin/systemctl start  mysqld.service