centos7 xtrabackup mysql 基本测试（4）---虚拟机环境 mysql 修改datadir（有问题）

centos7 xtrabackup mysql 基本测试（4）---虚拟机环境 mysql 修改datadir

参考

centos更改mysql数据库目录
https://blog.csdn.net/sinat_33151213/article/details/125079593

https://blog.csdn.net/jx_ZhangZhaoxuan/article/details/129139499

https://dev.mysql.com/doc/refman/8.4/en/selinux-file-context.html

https://developer.aliyun.com/article/1238771

创建目录

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sudo mkdir -p /opt/datadir/

首先，关闭MySQL服务：

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sudo systemctl stop mysqld
sudo systemctl status  mysqld

然后，复制原始datadir目录，作为新的目录：

sudo cp -rp /var/lib/mysql /opt/datadir/

sudo ls /opt/datadir/mysql/

接下来，修改 MySQL配置文件my.cnf：

sudo cp /etc/my.cnf /etc/org_my.cnf

sudo vi /etc/my.cnf

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# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html

[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/opt/datadir/mysql/
socket=/opt/datadir/mysql/mysql.sock

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

保存并关闭文件。此时，需要递归更改新目录的权限，以确保MySQL能够访问其中的数据：

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sudo chown -R mysql:mysql /opt/datadir/mysql
sudo chmod 750 /opt/datadir/mysql

最后，重新启动MySQL服务：

mysql>show variables like '%dir%';

如果启动失败, 使用setenforce 0命令,然后再启动一次试试

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show variables like '%dir';

selinux 与 mysql

semanage

ping www.baidu.com

检查并修改/etc/resolv.conf文件，确保DNS服务器地址正确。

nameserver 8.8.8.8

nameserver 8.8.4.4

CentOS7安装时使用"基础服务器"选项安装, 后发现没有semanage命令.

使用yum查询选项搜索

$root@localhost \~$ # yum provides semanage

按照搜索结果安装对应包即可解决

$root@localhost \~$ # yum install -y policycoreutils-python

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ping www.baidu.com
yum provides semanage
/usr/sbin/semanage
yum install -y policycoreutils-python-2.5-34.el7.x86_64
semanage 
semanage fcontext -l|grep mysqld_db_t

ls /opt/datadir/mysql/
ls
semanage fcontext -a -t mysqld_db_t "/opt/datadir/mysql(/.*)?"
restorecon -Rv /opt/datadir/mysql
semanage fcontext -l|grep mysqld_db_t

sudo systemctl status mysqld

mysql -u etc -p

show variables like '%dir';

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+---------------------------+----------------------------+
| Variable_name             | Value                      |
+---------------------------+----------------------------+
| basedir                   | /usr/                      |
| character_sets_dir        | /usr/share/mysql/charsets/ |
| datadir                   | /opt/datadir/mysql/        |
| innodb_data_home_dir      |                            |
| innodb_log_group_home_dir | ./                         |
| innodb_tmpdir             |                            |
| lc_messages_dir           | /usr/share/mysql/          |
| plugin_dir                | /usr/lib64/mysql/plugin/   |
| slave_load_tmpdir         | /tmp                       |
| tmpdir                    | /tmp                       |
+---------------------------+----------------------------+
10 rows in set (0.00 sec)