linux学习之centos（三）：mysql数据库的安装和配置

前言：mysql简介

说到数据库，我们大多想到的是关系型数据库，比如mysql、oracle、sqlserver等等，这些数据库软件在windows上安装都非常的方便，在Linux上如果要安装数据库，咱不得不首先推荐的是mysql数据库了，而且Mysql数据库的第一个版本就是发行在Linux系统上的。

MySQL是一个关系型数据库管理系统，由瑞典MySQL AB公司开发，目前属于Oracle公司。MySQL是一种关联数据库管理系统，关联数据库将数据保存在不同的表中，而不是将所有数据放在一个大仓库内，这样就增加了速度并提高了灵活性。MySQL的SQL语言是用于访问数据库的最常用标准化语言。MySQL软件采用了双授权政策（本词条“授权政策”），它分为社区版和商业版，由于其体积小、速度快、总体拥有成本低，尤其是开放源码这一特点，一般中小型网站的开发都选择MySQL作为网站数据库。由于其社区版的性能卓越，搭配PHP和Apache可组成良好的开发环境。

在Linux上安装mysql数据库，我们可以去其官网上下载mysql数据库的rpm包，http://dev.mysql.com/downloads/mysql/5.6.html#downloads，大家可以根据自己的操作系统去下载对应的数据库文件

--->本次是通过yum来进行mysql数据库的安装的，通过这种方式进行安装，可以将跟mysql相关的一些服务、jar包都给我们安装好，能省去很多不必要的麻烦！

一、卸载系统原有mysql

因为mysql数据库在Linux上实在是太流行了，所以目前下载的主流Linux系统版本基本上都集成了mysql数据库在里面

切换到root用户下操作：

[carsonzhu@localhost ~]$ su

查看该操作系统是否已经安装了mysql数据库：

[root@localhost carsonzhu]# rpm -qa | grep mysql

mysql-libs-5.1.71-1.el6.x86_64

然后我用下面的方式试图删除mysql（遇到了问题）：

[root@localhost carsonzhu]# rpm -e mysql-libs-5.1.71-1.el6.x86_64
error: Failed dependencies:
	libmysqlclient.so.16()(64bit) is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64
	libmysqlclient.so.16(libmysqlclient_16)(64bit) is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64
	mysql-libs is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64
[root@localhost carsonzhu]# rpm -e mysql-libs-5.1.71-1.el6.x86_64.rpm --nodeps
error: package mysql-libs-5.1.71-1.el6.x86_64.rpm is not installed

说是卸载的时候有依赖包，需要先把postfix-2:2.6.6-2.2.el6_1.x86_64卸载掉，rpm -e postfix-2:2.6.6-2.2.el6_1.x86_64也是不行！然后我搜索解决方法（CentOS 6.3 64位下彻底卸载mysql5.5.25图解教程）有：

如果存在CentOS自带mysql-libs-5.1.71-1.el6.x86_64使用下面的命令卸载即可

[root@localhost carsonzhu]# rpm -ev --nodeps mysql-libs-5.1.71-1.el6.x86_64
[root@localhost carsonzhu]# rpm -qa|grep -i mysql //查看mysql是否已经卸载成功
发现什么都没有了
[root@localhost carsonzhu]# find / -name mysql //查找之前老版本mysql的目录
发现也没有内容
（注：假设查找结果如下：
[root@localhost ~]# find / -name mysql
# /var/lib/mysql
# /var/lib/mysql/mysql
# /usr/lib64/mysql
删除对应的mysql目录
# rm -rf /var/lib/mysql
# rm -rf /var/lib/mysql
# rm -rf /usr/lib64/mysql
这里卸载后/etc/my.cnf不会删除，需要进行手工删除
# rm -rf /etc/my.cnf）

二、通过yum来安装mysql

查看yum上提供下载的mysql的版本信息：　　

[root@localhost carsonzhu]# yum list | grep mysql
apr-util-mysql.x86_64                  1.3.9-3.el6_0.1                   base
bacula-director-mysql.x86_64           5.0.0-13.el6                      base
bacula-storage-mysql.x86_64            5.0.0-13.el6                      base
dovecot-mysql.x86_64                   1:2.0.9-19.el6_7.2                updates
freeradius-mysql.x86_64                2.2.6-6.el6_7                     updates
libdbi-dbd-mysql.x86_64                0.8.3-5.1.el6                     base
mod_auth_mysql.x86_64                  1:3.0.0-11.el6_0.1                base
mysql.x86_64                           5.1.73-5.el6_7.1                  updates
mysql-bench.x86_64                     5.1.73-5.el6_7.1                  updates
mysql-connector-java.noarch            1:5.1.17-6.el6                    base
mysql-connector-odbc.x86_64            5.1.5r1144-7.el6                  base
mysql-devel.i686                       5.1.73-5.el6_7.1                  updates
mysql-devel.x86_64                     5.1.73-5.el6_7.1                  updates
mysql-embedded.i686                    5.1.73-5.el6_7.1                  updates
mysql-embedded.x86_64                  5.1.73-5.el6_7.1                  updates
mysql-embedded-devel.i686              5.1.73-5.el6_7.1                  updates
mysql-embedded-devel.x86_64            5.1.73-5.el6_7.1                  updates
mysql-libs.i686                        5.1.73-5.el6_7.1                  updates
mysql-libs.x86_64                      5.1.73-5.el6_7.1                  updates
mysql-server.x86_64                    5.1.73-5.el6_7.1                  updates
mysql-test.x86_64                      5.1.73-5.el6_7.1                  updates
php-mysql.x86_64                       5.3.3-46.el6_7.1                  updates
qt-mysql.i686                          1:4.6.2-28.el6_5                  base
qt-mysql.x86_64                        1:4.6.2-28.el6_5                  base
rsyslog-mysql.x86_64                   5.8.10-10.el6_6                   base
rsyslog7-mysql.x86_64                  7.4.10-3.el6_7.1                  updates

然后，可以通过输入 yum install -y mysql-server mysql mysql-devel 命令将mysql mysql-server mysql-devel都安装好(注:安装mysql时并不是安装了mysql客户端就相当于安装好了mysql数据库了，还需要安装mysql-server服务端才行)

等待一番时间后，yum会帮我们选择好安装mysql数据库所需要的软件以及其它附属的一些软件

[root@localhost carsonzhu]# yum install -y mysql-server mysql mysql-deve
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: mirrors.zju.edu.cn
 * extras: mirrors.skyshe.cn
 * updates: mirrors.skyshe.cn
base                                                     | 3.7 kB     00:00
extras                                                   | 3.4 kB     00:00
updates                                                  | 3.4 kB     00:00
Setting up Install Process
No package mysql-deve available.
Resolving Dependencies
--> Running transaction check
---> Package mysql.x86_64 0:5.1.73-5.el6_7.1 will be installed
--> Processing Dependency: mysql-libs = 5.1.73-5.el6_7.1 for package: mysql-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: libmysqlclient_r.so.16(libmysqlclient_16)(64bit) for package: mysql-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: libmysqlclient.so.16(libmysqlclient_16)(64bit) for package: mysql-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: libmysqlclient_r.so.16()(64bit) for package: mysql-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: libmysqlclient.so.16()(64bit) for package: mysql-5.1.73-5.el6_7.1.x86_64
---> Package mysql-server.x86_64 0:5.1.73-5.el6_7.1 will be installed
--> Processing Dependency: perl-DBI for package: mysql-server-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: perl-DBD-MySQL for package: mysql-server-5.1.73-5.el6_7.1.x86_64
--> Processing Dependency: perl(DBI) for package: mysql-server-5.1.73-5.el6_7.1.x86_64
--> Running transaction check
---> Package mysql-libs.x86_64 0:5.1.73-5.el6_7.1 will be installed
---> Package perl-DBD-MySQL.x86_64 0:4.013-3.el6 will be installed
---> Package perl-DBI.x86_64 0:1.609-4.el6 will be installed
--> Finished Dependency Resolution
 
Dependencies Resolved
 
================================================================================
 Package              Arch         Version                  Repository     Size
================================================================================
Installing:
 mysql                x86_64       5.1.73-5.el6_7.1         updates       894 k
 mysql-server         x86_64       5.1.73-5.el6_7.1         updates       8.6 M
Installing for dependencies:
 mysql-libs           x86_64       5.1.73-5.el6_7.1         updates       1.2 M
 perl-DBD-MySQL       x86_64       4.013-3.el6              base          134 k
 perl-DBI             x86_64       1.609-4.el6              base          705 k
 
Transaction Summary
================================================================================
Install       5 Package(s)
 
Total download size: 12 M
Installed size: 33 M
Downloading Packages:
(1/5): mysql-5.1.73-5.el6_7.1.x86_64.rpm                 | 894 kB     00:00
(2/5): mysql-libs-5.1.73-5.el6_7.1.x86_64.rpm            | 1.2 MB     00:01
(3/5): mysql-server-5.1.73-5.el6_7.1.x86_64.rpm          | 8.6 MB     00:08
(4/5): perl-DBD-MySQL-4.013-3.el6.x86_64.rpm             | 134 kB     00:00
(5/5): perl-DBI-1.609-4.el6.x86_64.rpm                   | 705 kB     00:00
--------------------------------------------------------------------------------
Total                                           1.0 MB/s |  12 MB     00:11
warning: rpmts_HdrFromFdno: Header V3 RSA/SHA256 Signature, key ID c105b9de: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Importing GPG key 0xC105B9DE:
 Userid : CentOS-6 Key (CentOS 6 Official Signing Key) <centos-6-key@centos.org>
 Package: centos-release-6-5.el6.centos.11.1.x86_64 (@anaconda-CentOS-201311272149.x86_64/6.5)
 From   : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
** Found 3 pre-existing rpmdb problem(s), 'yum check' output follows:
2:postfix-2.6.6-2.2.el6_1.x86_64 has missing requires of libmysqlclient.so.16()(64bit)
2:postfix-2.6.6-2.2.el6_1.x86_64 has missing requires of libmysqlclient.so.16(libmysqlclient_16)(64bit)
2:postfix-2.6.6-2.2.el6_1.x86_64 has missing requires of mysql-libs
  Installing : mysql-libs-5.1.73-5.el6_7.1.x86_64                           1/5
  Installing : perl-DBI-1.609-4.el6.x86_64                                  2/5
  Installing : perl-DBD-MySQL-4.013-3.el6.x86_64                            3/5
  Installing : mysql-5.1.73-5.el6_7.1.x86_64                                4/5
  Installing : mysql-server-5.1.73-5.el6_7.1.x86_64                         5/5
  Verifying  : perl-DBD-MySQL-4.013-3.el6.x86_64                            1/5
  Verifying  : perl-DBI-1.609-4.el6.x86_64                                  2/5
  Verifying  : mysql-libs-5.1.73-5.el6_7.1.x86_64                           3/5
  Verifying  : mysql-5.1.73-5.el6_7.1.x86_64                                4/5
  Verifying  : mysql-server-5.1.73-5.el6_7.1.x86_64                         5/5 
 
Installed:
  mysql.x86_64 0:5.1.73-5.el6_7.1     mysql-server.x86_64 0:5.1.73-5.el6_7.1    
 
Dependency Installed:
  mysql-libs.x86_64 0:5.1.73-5.el6_7.1    perl-DBD-MySQL.x86_64 0:4.013-3.el6
  perl-DBI.x86_64 0:1.609-4.el6          
 
Complete!

此时，我们通过如下命令查看刚安装好的mysql-server的版本：

[root@localhost carsonzhu]# rpm -qi mysql-server
Name        : mysql-server                 Relocations: (not relocatable)
Version     : 5.1.73                            Vendor: CentOS
Release     : 5.el6_7.1                     Build Date: 2016年03月23日 星期三 02时10分16秒
Install Date: 2016年05月22日 星期日 14时37分04秒      Build Host: c6b8.bsys.dev.centos.org
Group       : Applications/Databases        Source RPM: mysql-5.1.73-5.el6_7.1.src.rpm
Size        : 25883011                         License: GPLv2 with exceptions
Signature   : RSA/SHA1, 2016年03月23日 星期三 03时36分21秒, Key ID 0946fca2c105b9de
Packager    : CentOS BuildSystem <http://bugs.centos.org>
URL         : http://www.mysql.com
Summary     : The MySQL server and related files
Description :
MySQL is a multi-user, multi-threaded SQL database server. MySQL is a
client/server implementation consisting of a server daemon (mysqld)
and many different client programs and libraries. This package contains
the MySQL server and some accompanying files and directories.

三、mysql数据库的初始化和相关配置

我们在安装完mysql数据库以后，会发现会多出一个mysqld的服务，这个就是咱们的数据库服务，我们通过输入 service mysqld start 命令就可以启动我们的mysql服务。

注：如果是第一次启动mysql服务，mysql服务器首先会进行初始化的配置，如：

[root@localhost carsonzhu]# service mysqld start
初始化 MySQL 数据库： Installing MySQL system tables...
OK
Filling help tables...
OK
 
To start mysqld at boot time you have to copy
support-files/mysql.server to the right place for your system
 
PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
To do so, start the server, then issue the following commands:
 
/usr/bin/mysqladmin -u root password 'new-password'
/usr/bin/mysqladmin -u root -h localhost.localdomain password 'new-password'
 
Alternatively you can run:
/usr/bin/mysql_secure_installation
 
which will also give you the option of removing the test
databases and anonymous user created by default.  This is
strongly recommended for production servers.
 
See the manual for more instructions.
 
You can start the MySQL daemon with:
cd /usr ; /usr/bin/mysqld_safe &
 
You can test the MySQL daemon with mysql-test-run.pl
cd /usr/mysql-test ; perl mysql-test-run.pl
 
Please report any problems with the /usr/bin/mysqlbug script!
 
                                                           [确定]
正在启动 mysqld：                                          [确定]

我们会看到第一次启动mysql服务器以后会提示非常多的信息，目的就是对mysql数据库进行初始化操作，再次重启mysql服务时，就不会提示那么多信息了：

[root@localhost carsonzhu]# service mysqld start
正在启动 mysqld：                                          [确定]

查看mysql服务是否为开机自动启动：

[root@localhost carsonzhu]# chkconfig --list | grep mysqld
mysqld         	0:关闭	1:关闭	2:关闭	3:关闭	4:关闭	5:关闭	6:关闭

将其设置为开机启动：

[root@localhost carsonzhu]# chkconfig mysqld on
[root@localhost carsonzhu]# chkconfig --list | grep mysqld
mysqld         	0:关闭	1:关闭	2:启用	3:启用	4:启用	5:启用	6:关闭

当然，想再次关闭开机启动也很简单：

[root@localhost carsonzhu]# chkconfig mysqld off
[root@localhost carsonzhu]# chkconfig --list | grep mysqld
mysqld         	0:关闭	1:关闭	2:关闭	3:关闭	4:关闭	5:关闭	6:关闭

mysql数据库安装完以后只会有一个root管理员账号，但是此时的root账号还并没有为其设置密码，在第一次启动mysql服务时，会进行数据库的一些初始化工作，在输出的一大串信息中，有这样一行信息 ：

/usr/bin/mysqladmin -u root password 'new-password'　　// 为root账号设置密码　　

设置mysql数据库的root账号（(注：这个root账号是mysql的root账号，非Linux的root账号)）：

[root@localhost carsonzhu]# mysqladmin -u root password 'carsonzhu'

（将root账号密码设置为carsonzhu）　　

登录mysql数据库：

[root@localhost carsonzhu]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.73 Source distribution
 
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
 
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 
mysql> show databases ;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test               |
+--------------------+
3 rows in set (0.02 sec)
 
mysql>

四、mysql数据库的主要配置文件

1、/etc/my.cnf 是mysql的主配置文件

[root@localhost carsonzhu]# cd
[root@localhost ~]# ls
anaconda-ks.cfg  install.log  install.log.syslog
[root@localhost ~]# cd /home
[root@localhost home]# ls
carsonzhu
[root@localhost home]# find / -name etc
/usr/local/etc
/usr/lib/vmware-tools/lib32/libconf/etc
/usr/lib/vmware-tools/lib64/libconf/etc
/usr/etc
/usr/share/doc/oddjob-0.30/sample/etc
/usr/share/festival/lib/etc
/usr/lib64/festival/etc
/tmp/vmware-tools-distrib/lib/lib32/libconf/etc
/tmp/vmware-tools-distrib/lib/lib64/libconf/etc
/tmp/vmware-tools-distrib/caf/etc
/tmp/vmware-tools-distrib/etc
/etc
[root@localhost home]# cd /
[root@localhost /]# ls
bin    dev   lib         media  net   root     sr0  tmp    var
boot   etc   lib64       misc   opt   sbin     srv  Tools
cdrom  home  lost+found  mnt    proc  selinux  sys  usr
[root@localhost /]# cd etc

[root@localhost /]# ls
bin    dev   lib         media  net   root     sr0  tmp    var
boot   etc   lib64       misc   opt   sbin     srv  Tools
cdrom  home  lost+found  mnt    proc  selinux  sys  usr
[root@localhost /]# cd etc
[root@localhost etc]# ls
abrt                     hp                            printcap
acpi                     httpd                         profile
adjtime                  idmapd.conf                   profile.d
aliases                  init                          protocols
aliases.db               init.d                        pulse
alsa                     inittab                       purple
alternatives             inputrc                       quotagrpadmins
anacrontab               ipa                           quotatab
anthy-conf               iproute2                      rc
asound.conf              issue                         rc0.d
at.deny                  issue.net                     rc1.d
audisp                   java                          rc2.d
audit                    jvm                           rc3.d
autofs_ldap_auth.conf    jvm-commmon                   rc4.d
auto.master              kde                           rc5.d
auto.misc                kdump-adv-conf                rc6.d
auto.net                 kdump.conf                    rc.d
auto.smb                 krb5.conf                     rc.local
avahi                    latrace.conf                  rc.sysinit
bash_completion.d        latrace.d                     readahead.conf
bashrc                   ld.so.cache                   redhat-lsb
blkid                    ld.so.conf                    redhat-release
bluetooth                ld.so.conf.d                  request-key.conf
bonobo-activation        libaudit.conf                 request-key.d
cas.conf                 libreport                     resolv.conf
centos-release           libuser.conf                  rpc
certmonger               localtime                     rpm
chkconfig.d              login.defs                    rsyslog.conf
ConsoleKit               logrotate.conf                rsyslog.d
cron.d                   logrotate.d                   rwtab
cron.daily               lsb-release                   rwtab.d
cron.deny                lsb-release.d                 samba
cron.hourly              ltrace.conf                   sane.d
cron.monthly             lvm                           sasl2
crontab                  magic                         scl
cron.weekly              mailcap                       securetty
crypttab                 mail.rc                       security
csh.cshrc                makedev.d                     selinux
csh.login                man.config                    services
cups                     maven                         sestatus.conf
dbus-1                   mime.types                    setuptool.d
default                  mke2fs.conf                   sgml
depmod.d                 modprobe.d                    shadow
dhcp                     motd                          shadow-
DIR_COLORS               mtab                          shells
DIR_COLORS.256color      mtools.conf                   skel
DIR_COLORS.lightbgcolor  my.cnf                        smartd.conf
dnsmasq.conf             nanorc                        snmp
dnsmasq.d                netconfig                     sos.conf
dracut.conf              NetworkManager                sound
dracut.conf.d            networks                      ssh
drirc                    nfsmount.conf                 ssl
enscript.cfg             nsswitch.conf                 sssd
environment              ntp                           statetab
ethers                   ntp.conf                      statetab.d
event.d                  obex-data-server              sudo.conf
exports                  oddjob                        sudoers
favicon.png              oddjobd.conf                  sudoers.d
festival                 oddjobd.conf.d                sudo-ldap.conf
filesystems              openldap                      sysconfig
fonts                    opt                           sysctl.conf
foomatic                 PackageKit                    system-release
fprintd.conf             pam.d                         system-release-cpe
fstab                    pango                         terminfo
gai.conf                 passwd                        tpvmlp.conf
gconf                    passwd-                       Trolltech.conf
gcrypt                   pbm2ppa.conf                  udev
gdm                      pcmcia                        updatedb.conf
ghostscript              pinforc                       vimrc
gnome-vfs-2.0            pkcs11                        virc
gnupg                    pki                           vmware-caf
group                    plymouth                      vmware-tools
group-                   pm                            warnquota.conf
grub.conf                pm-utils-hd-apm-restore.conf  wgetrc
gshadow                  pnm2ppa.conf                  wpa_supplicant
gshadow-                 polkit-1                      X11
gssapi_mech.conf         popt.d                        xdg
gtk-2.0                  portreserve                   xinetd.d
hal                      postfix                       xml
host.conf                ppp                           yp.conf
hosts                    prelink.cache                 yum
hosts.allow              prelink.conf                  yum.conf
hosts.deny               prelink.conf.d                yum.repos.d

[root@localhost etc]# ls my.cnf
my.cnf
[root@localhost etc]# cat my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
 
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

2、/var/lib/mysql   mysql数据库的数据库文件存放位置

[root@localhost etc]# cd /var
[root@localhost var]# cd lib/mysql
[root@localhost mysql]# ls -1
ibdata1
ib_logfile0
ib_logfile1
mysql         //mysql数据库安装时默认的两个数据库文件
mysql.sock
test         //mysql数据库安装时默认的两个数据库文件

自己创建一个数据库，并验证该数据库文件的存放位置：

[root@localhost mysql]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.1.73 Source distribution
 
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
 
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 
mysql> create database carsontest ;
Query OK, 1 row affected (0.01 sec)
 
mysql> exit
Bye
[root@localhost mysql]# ls -1
carsontest
ibdata1
ib_logfile0
ib_logfile1
mysql
mysql.sock
test
[root@localhost mysql]# cd carsontest
[root@localhost carsontest]# ls
db.opt

3、/var/log mysql数据库的日志输出存放位置

[root@localhost carsontest]# cd
[root@localhost ~]# cd /var/log
[root@localhost log]# ls
anaconda.ifcfg.log    gdm                secure-20160517
anaconda.log          httpd              secure-20160522
anaconda.program.log  lastlog            spice-vdagent.log
anaconda.storage.log  maillog            spooler
anaconda.syslog       maillog-20160305   spooler-20160305
anaconda.xlog         maillog-20160517   spooler-20160517
anaconda.yum.log      maillog-20160522   spooler-20160522
audit                 messages           sssd
boot.log              messages-20160305  tallylog
btmp                  messages-20160517  vmware-caf
btmp-20160517         messages-20160522  vmware-install.log
ConsoleKit            mysqld.log         vmware-vmsvc.log
cron                  ntpstats           wpa_supplicant.log
cron-20160305         pm-powersave.log   wtmp
cron-20160517         ppp                Xorg.0.log
cron-20160522         prelink            Xorg.0.log.old
cups                  sa                 Xorg.9.log
dmesg                 samba              yum.log
dmesg.old             secure
dracut.log            secure-20160305

因为我们的mysql数据库是可以通过网络访问的，并不是一个单机版数据库，其中使用的协议是 tcp/ip 协议，我们都知道mysql数据库绑定的端口号是 3306 ，所以我们可以通过 netstat -anp 命令来查看一下，Linux系统是否在监听 3306 这个端口号：

[root@localhost log]# netstat -anp | more
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address               Foreign Address
State       PID/Program name
tcp        0      0 0.0.0.0:38029               0.0.0.0:*
LISTEN      1788/rpc.statd
tcp        0      0 0.0.0.0:111                 0.0.0.0:*
LISTEN      1742/rpcbind
tcp        0      0 0.0.0.0:22                  0.0.0.0:*
LISTEN      1961/sshd
tcp        0      0 127.0.0.1:631               0.0.0.0:*
LISTEN      1845/cupsd
tcp        0      0 127.0.0.1:25                0.0.0.0:*
LISTEN      2131/master
tcp        0      0 0.0.0.0:3306                0.0.0.0:*
LISTEN      20295/mysqld
tcp        1      0 192.168.1.20:53892          61.213.168.17:80
CLOSE_WAIT  2723/clock-applet
tcp        1      0 192.168.1.20:53891          61.213.168.17:80
CLOSE_WAIT  2723/clock-applet
tcp        0      0 :::40843                    :::*
LISTEN      1788/rpc.statd
tcp        0      0 :::111                      :::*
LISTEN      1742/rpcbind

结果如上所示，Linux系统监听的3306端口号就是我们的mysql数据库！

可参考文章：Linux学习之CentOS(十三)--CentOS6.4下Mysql数据库的安装与配置

另外一种安装方式：CentOS7安装mysql5.6.26