CentOS6.5mysql installation _ MySQL

1. uninstalling the original mysqlmysql database is too popular on Linux, so the mainstream Linux system versions downloaded are basically integrated with the mysql database, you can run the following command to check whether the mysql database has been installed on our operating system [root 1, uninstall the original mysql

Mysql databases are too popular in Linux, so the mainstream Linux system versions currently downloaded are basically integrated with mysql databases, run the following command to check whether the mysql database has been installed on the operating system:

[Root @ hadoop1 ~] # Rpm-qa | grep mysql // This command will check whether the mysql database has been installed on the operating system

If yes, run the rpm-e command or the rpm-e -- nodeps command to uninstall it.

[Root @ hadoop1 ~] # Rpm-e mysql // normal deletion mode [root @ hadoop1 ~] # Rpm-e -- nodeps mysql // strong deletion mode. if the above command is used to delete other dependent files, you can use this command to forcibly delete them.

After deletion, run the rpm-qa | grep mysql command to check whether mysql has been uninstalled successfully !!

2. install mysql using yum

I am using yum to install mysql databases. First, we can enter the yum list | grep mysql command to view the downloadable mysql database version on yum:

[root@hadoop1 ~]# yum list | grep mysql

You can get the downloadable version of the mysql database on the yum server:

Then, run the yum install-y mysql-server mysql-devel command to install mysql-server mysql-devel (Note: When installing mysql, we have installed the mysql database instead of the mysql client. we also need to install the mysql-server.)

[root@hadoop1 ~]# yum install -y mysql-server mysql mysql-deve

Installing the mysql database using yum saves a lot of unnecessary trouble. when the following result appears, it indicates that the mysql database has been successfully installed.

3. Mysql database initialization and related configuration

After installing the mysql database, you will find an additional mysqld service. this is our database service. we can start our mysql service by entering the service mysqld start command.

Note: If we start the mysql service for the first time, the mysql server will first perform initialization configuration, for example:

When using the mysql database, we have to start the mysqld service first. we can run the chkconfig -- list | grep mysqld command to check whether the mysql service is automatically started upon startup, for example:

[Root @ hadoop1 ~] # Chkconfig -- list | grep mysqldmysqld 0: close 1: close 2: Close 3: close 4: Close 5: close 6: Close

We found that the mysqld service is not automatically started when it is started. of course, you can use the chkconfig mysqld on command to set it to boot, so that you do not need to start it manually every time.

[Root @ hadoop1 ~] # Chkconfig mysqld on [root @ hadoop1 ~] # Chkconfig -- list | grep mysqlmysqld 0: disable 1: disable 2: Enable 3: Enable 4: enable 5: Enable 6: disable

After the mysql database is installed, there will be only one root administrator account, but the root account has not set a password for it. when the mysql service is started for the first time, some database initialization will be performed, in a large string of output information, we can see such a line of information:

Therefore, we can use this command to set a password for our root account (note: This root account is the root account of mysql, not the root account of Linux ).

[root@hadoop1 ~]# mysqladmin -u root password 'root'

Main configuration file of mysql database

1./Etc/my. cnfThis is the main configuration file of mysql.

We can check some information about this file.

[root@hadoop1 etc]# ls my.cnf my.cnf[root@hadoop1 etc]# cat my.cnf [mysqld]datadir=/var/lib/mysqlsocket=/var/lib/mysql/mysql.sockuser=mysql# Disabling symbolic-links is recommended to prevent assorted security riskssymbolic-links=0[mysqld_safe]log-error=/var/log/mysqld.logpid-file=/var/run/mysqld/mysqld.pid

2./Var/lib/mysqlDatabase file storage location of the mysql database

The database files of our mysql database are usually stored in the/ver/lib/mysql directory.

[Root @ hadoop1 ~] # Cd/var/lib/mysql/[root @ hadoop1 mysql] # ls-l total usage 20488-rw-rw ----. 1 mysql 10485760 April 6 22:01 ibdata1-rw-rw ----. 1 mysql 5242880 April 6 22:01 ib_logfile0-rw-rw ----. 1 mysql 5242880 April 6 21:59 ib_logfile1drwx ------. 2 mysql 4096 21:59 mysql // These two are the default two database files srwxrwxrwx during mysql database installation. 1 mysql 0 April 6 22:01 mysql. sockdrwx ------. 2 mysql 4096 April 6 21:59 test // These two are the default two database files during mysql database installation

We can create a database to verify the storage location of the database file.

Create a database: mysql> create database x1; Query OK, 1 row affected (0.00 sec) [root @ hadoop1 mysql] # ls-l total usage 202.16-rw-rw ----. 1 mysql 10485760 April 6 22:01 ibdata1-rw-rw ----. 1 mysql 5242880 April 6 22:01 ib_logfile0-rw-rw ----. 1 mysql 5242880 April 6 21:59 ib_logfile1drwx ------. 2 mysql 4096 April 6 21:59 mysqlsrwxrwxrwx. 1 mysql 0 April 6 22:01 mysql. sockdrwx ------. 2 mysql 4096 April 6 21:59 testdrwx ------. 2 mysql 4096 22:15, December 1, April 6/new database [root @ hadoop1 mysql] # cd xiaoluo/[root @ hadoop1 x1] # lsdb. opt

3./Var/logLog output location of the mysql database

Some log output locations of our mysql database are stored in the/var/log directory.

[root@hadoop1 x1]# cd [root@hadoop1 ~]# cd /var/log[root@hadoop1 log]# lsamanda                cron           maillog-20130331   spice-vdagent.loganaconda.ifcfg.log    cron-20130331  mcelog             spooleranaconda.log          cups           messages           spooler-20130331anaconda.program.log  dirsrv         messages-20130331  sssdanaconda.storage.log  dmesg          mysqld.log         tallyloganaconda.syslog       dmesg.old      ntpstats           tomcat6anaconda.xlog         dracut.log     piranha            wpa_supplicant.loganaconda.yum.log      gdm            pm-powersave.log   wtmpaudit                 httpd          ppp                Xorg.0.logboot.log              ibacm.log      prelink            Xorg.0.log.oldbtmp                  lastlog        sa                 Xorg.1.logbtmp-20130401         libvirt        samba              Xorg.2.logcluster               luci           secure             Xorg.9.logConsoleKit            maillog        secure-20130331    yum.log

The mysqld. log file is the log information generated when we operate on the mysql database. by viewing this log file, we can obtain a lot of information.

Because our mysql database is accessible through the network, it is not a standalone database, and the protocol used is the TCP/IP protocol. we all know that the port number bound to the mysql database is 3306, so we can run the netstat-anp command to check whether the Linux system is listening for the port number 3306:

The result is as shown above. the port number 3306 monitored by Linux is our mysql database !!!!