Solve the problem that MySQL cannot be started on centos.

1./etc/My. CNF Default Configuration

The configuration file is as follows:

[Mysqld]

Datadir =/var/lib/MySQL

Socket =/var/lib/MySQL. Sock

# Default
To using old password format for compatibility with MySQL 3.x

# Clients
(Those using the mysqlclient10 compatibility package ).

Old_passwords = 1

[Mysql. Server]

User = MySQL

Basedir =/var/lib

[Mysqld_safe]

Log-error =/var/log/mysqld. Log

PID-file =/var/run/mysqld. PID

 

Because the project needs to modify the value of datadir, as follows:

Datadir =/usr/local/project/etc/Data

 

Start MySql in centos:

[Wzhwho @ local ~] # Service
Mysqld start

Starting mysqld daemon [failed]

 

2. Check the error log first.

The default path for MySQL Log files installed with RPM is/var/log/mysqld. log.

Mysqld started

InnoDB: operating system error number 13 in a file operation.

InnoDB: the error means mysqld does not have the access rights

InnoDB: the directory.

InnoDB: file name/usr/local/project/etc/data/ibdata1

InnoDB: File Operation call: 'create '.

InnoDB: cannot continue operation.

Mysqld ended

 

The log shows that the MySQL data file directory does not have the permission, therefore, I need to set the permission and owner for the/usr/local/project/etc/DATA DIRECTORY according to the permission of the/var/lib/MySQL directory.

[Wzhwho @ local ~] # Ll
/Var/lib

Drwxr-X-r-x 1 MySQL
4
Apr 11
2009
MySQL

[Wzhwho @ local ~] # Ll
/Var/lib

[Wzhwho @ local ~] Chown-r MYSQL: MySQL/usr/local/project/etc/Data

[Wzhwho @ local ~] Chmod-r 755/usr/local/project/etc/Data

[Wzhwho @ local ~] # Ll
/Usr/local/project/etc

Drwxr-X-r-x 1 MySQL
4
Apr 11
2009
Data

Then I started MySQL again, but it still failed with the same log information.

 

3. modify the configuration file/etc/SELinux/config

Finally, I found such a reply in an email from a foreign friend:

If you are using SE Linux, set it
Permissive mode by editing/etc/SELinux/config

And changing

SELinux = enforcing
To SELinux = permissive

This solved all of my problems with

"Operating System error number 13 in a file operation" error

 

Therefore, if SELinux is the final issue, enter the command LS-Z and you will find the tag on the file or folder. If a file is created when SELinux is opened, even if SELinux is disabled, its permission control still works. You can use chcon to change permissions.

 

4. MySQL is successfully started.

[Wzhwho @ local ~] # Service
Mysqld start

Starting mysqld daemon [OK]