rpm -qa | grep -i mysql  //grep -i是不分大小写字符查询，只要含有mysql就显示

mysql-libs-5.1.71-1.el6.i686  //它是好几个软件的依赖，其中在mini版本中postfix软件依赖mysql-libs，网络上很多建议都是直接删除，yum remove mysql-libs 或者 rpm -e --nodeps mysql-libs-5.1.71-1.el6.i686，总觉得这样做不好。

查找mysql官方资料，得到安装方法是用MySQL-shared-compat将mysql-libs-5.1.71-1.el6.i686替换为同版本后在安装mysql。

#tar xvf MySQL-5.6.21-1.el6.i686.rpm-bundle.tar MySQL-client-5.6.21-1.el6.i686.rpmMySQL-devel-5.6.21-1.el6.i686.rpmMySQL-shared-5.6.21-1.el6.i686.rpmMySQL-test-5.6.21-1.el6.i686.rpmMySQL-server-5.6.21-1.el6.i686.rpmMySQL-embedded-5.6.21-1.el6.i686.rpm#ls -ltotal 415068-rw-r--r--. 1 root root  210442240 Nov 11 11:12 MySQL-5.6.21-1.el6.i686.rpm-bundle.tar-rw-r--r--. 1 7155 wheel  17813608 Sep 12 16:25 MySQL-client-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 7155 wheel   3131328 Sep 12 16:25 MySQL-devel-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 7155 wheel  83106000 Sep 12 16:25 MySQL-embedded-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 7155 wheel  54611632 Sep 12 16:26 MySQL-server-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 7155 wheel   1878756 Sep 12 16:27 MySQL-shared-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 root root    4141488 Nov 18 14:42 MySQL-shared-compat-5.6.21-1.el6.i686.rpm-rw-r--r--. 1 7155 wheel  49887932 Sep 12 16:27 MySQL-test-5.6.21-1.el6.i686.rpm

# rpm -i MySQL-shared-compat-5.6.21-1.el6.i686.rpm# rpm -qa | grep -i mysqlmysql-libs-5.1.71-1.el6.i686MySQL-shared-compat-5.6.21-1.el6.i686# yum remove mysql-libs

# rpm -ivh --test MySQL-server-5.6.21-1.el6.i686.rpm# yum install perl

# rpm -ivh  MySQL-server-5.6.21-1.el6.i686.rpmPreparing...                ########################################### [100%]   1:MySQL-server           ########################################### [100%]………………………………A RANDOM PASSWORD HAS BEEN SET FOR THE MySQL root USER !You will find that password in '/root/.mysql_secret'.You must change that password on your first connect,no other statement but 'SET PASSWORD' will be accepted.See the manual for the semantics of the 'password expired' flag.Also, the account for the anonymous user has been removed.In addition, you can run:  /usr/bin/mysql_secure_installation………………………………# rpm -ivh  MySQL-client-5.6.21-1.el6.i686.rpmPreparing...                ########################################### [100%]   1:MySQL-client           ########################################### [100%]

#more .mysql_secret# The random password set for the root user at Tue Nov 18 22:57:46 2014 (local time): NljqL63OYlGo5cqy    <– 得到root访问mysql的密码：NljqL63OYlGo5cqy# service mysql startStarting MySQL... SUCCESS! # /usr/bin/mysql_secure_installation --user=mysqlNOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!In order to log into MySQL to secure it, we'll need the currentpassword for the root user.  If you've just installed MySQL, andyou haven't set the root password yet, the password will be blank,so you should just press enter here.Enter current password for root (enter for none):    <–使用刚才得到的root的密码 NljqL63OYlGo5cqyOK, successfully used password, moving on...Setting the root password ensures that nobody can log into the MySQLroot user without the proper authorisation.You already have a root password set, so you can safely answer 'n'.Change the root password? [Y/n] y   <– 是否更换root用户密码，输入y并回车，强烈建议更换New password:      <– 设置root用户的密码Re-enter new password:    <– 再输入一次你设置的密码Password updated successfully!Reloading privilege tables.. ... Success!By default, a MySQL installation has an anonymous user, allowing anyoneto log into MySQL without having to have a user account created forthem.  This is intended only for testing, and to make the installationgo a bit smoother.  You should remove them before moving into aproduction environment.Remove anonymous users? [Y/n] y   <– 是否删除匿名用户,生产环境建议删除，所以输入y并回车 ... Success!Normally, root should only be allowed to connect from 'localhost'.  Thisensures that someone cannot guess at the root password from the network.Disallow root login remotely? [Y/n] y    <–是否禁止root远程登录,根据自己的需求选择Y/n并回车,建议禁止 ... Success!By default, MySQL comes with a database named 'test' that anyone canaccess.  This is also intended only for testing, and should be removedbefore moving into a production environment.Remove test database and access to it? [Y/n] y    <– 是否删除test数据库,输入y并回车 - Dropping test database... ... Success! - Removing privileges on test database... ... Success!Reloading the privilege tables will ensure that all changes made so farwill take effect immediately.Reload privilege tables now? [Y/n] y   是否重新加载权限表，输入y并回车 ... Success!All done!  If you've completed all of the above steps, your MySQLinstallation should now be secure.Thanks for using MySQL!Cleaning up...

#  chkconfigauditd          0:off   1:off   2:on    3:on    4:on    5:on    6:offblk-availability        0:off   1:on    2:on    3:on    4:on    5:on    6:offcrond           0:off   1:off   2:on    3:on    4:on    5:on    6:offip6tables       0:off   1:off   2:on    3:on    4:on    5:on    6:offiptables        0:off   1:off   2:on    3:on    4:on    5:on    6:offiscsi           0:off   1:off   2:off   3:on    4:on    5:on    6:offiscsid          0:off   1:off   2:off   3:on    4:on    5:on    6:offlvm2-monitor    0:off   1:on    2:on    3:on    4:on    5:on    6:offmdmonitor       0:off   1:off   2:on    3:on    4:on    5:on    6:offmultipathd      0:off   1:off   2:off   3:off   4:off   5:off   6:offmysql           0:off   1:off   2:on    3:on    4:on    5:on    6:off   <-看到这个OK了netconsole      0:off   1:off   2:off   3:off   4:off   5:off   6:offnetfs           0:off   1:off   2:off   3:on    4:on    5:on    6:offnetwork         0:off   1:off   2:on    3:on    4:on    5:on    6:offpostfix         0:off   1:off   2:on    3:on    4:on    5:on    6:offrdisc           0:off   1:off   2:off   3:off   4:off   5:off   6:offrestorecond     0:off   1:off   2:off   3:off   4:off   5:off   6:offrsyslog         0:off   1:off   2:on    3:on    4:on    5:on    6:offsaslauthd       0:off   1:off   2:off   3:off   4:off   5:off   6:offsshd            0:off   1:off   2:on    3:on    4:on    5:on    6:offudev-post       0:off   1:on    2:on    3:on    4:on    5:on    6:off