某台mysql数据库，突然掉电，重启系统启动数据库失败，进入数据库目录发现数据文件完好，从新初始化数据库，从数据文件中恢复数据
一、将/home/mysql-5.7.26/data/目录复制出来
[root@orderer home]# cd mysql-5.7.26/ [root@orderer mysql-5.7.26]# cp -R data/ ../data_bak
二、删除/home/mysql-5.7.26/data/目录，因为初始化数据库的时候，data目录必须为空
[root@orderer mysql-5.7.26]# rm -rf data/ [root@orderer mysql-5.7.26]# mkdir data
由于我是root账户操作的，所以将data目录权限赋予mysql用户
[root@orderer mysql-5.7.26]# chown -R mysql:mysql data
三、重新初始化数据库
[root@orderer home]# mysqld_safe --defaults-file=/etc/mysql/my.cnf --initialize --basedir=/home/mysql-5.7.26/ --datadir=/home/mysql-5.7.26/data/ 2020-01-19T07:11:22.220590Z mysqld_safe Logging to '/home/mysql-5.7.26/log/mysqld.log'. 2020-01-19T07:11:22.266396Z mysqld_safe Starting mysqld daemon with databases from /home/mysql-5.7.26/data 2020-01-19T07:11:33.111853Z mysqld_safe mysqld from pid file /home/mysql-5.7.26/run/mysqld.pid ended
此时，查看data目录下已经生成了相关文件
[root@orderer mysql-5.7.26]# ll data ??? 110668 -rw-r----- 1 mysql mysql 56 1? 19 15:11 auto.cnf -rw------- 1 mysql mysql 1680 1? 19 15:11 ca-key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 ca.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 client-cert.pem -rw------- 1 mysql mysql 1680 1? 19 15:11 client-key.pem -rw-r----- 1 mysql mysql 419 1? 19 15:11 ib_buffer_pool -rw-r----- 1 mysql mysql 12582912 1? 19 15:11 ibdata1 -rw-r----- 1 mysql mysql 50331648 1? 19 15:11 ib_logfile0 -rw-r----- 1 mysql mysql 50331648 1? 19 15:11 ib_logfile1 -rw-r----- 1 mysql mysql 177 1? 19 15:11 master-18-69.000001 -rw-r----- 1 mysql mysql 22 1? 19 15:11 master-18-69.index drwxr-x--- 2 mysql mysql 4096 1? 19 15:11 mysql drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 performance_schema -rw------- 1 mysql mysql 1680 1? 19 15:11 private_key.pem -rw-r--r-- 1 mysql mysql 452 1? 19 15:11 public_key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 server-cert.pem -rw------- 1 mysql mysql 1676 1? 19 15:11 server-key.pem drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 sys
查找mysql.log日志过滤"temporary password"，得到系统生成的初始随机密码，第一次登陆使用
[root@orderer mysql-5.7.26]# cat /home/mysql-5.7.26/log/mysqld.log|grep 'temporary password' 2020-01-19T07:11:25.453456Z 1 [Note] A temporary password is generated for root@localhost: PcrY;58llX3<
四、启动mysql
[root@orderer home]# mysqld_safe --defaults-file=/etc/mysql/my.cnf 2020-01-19T07:16:34.019182Z mysqld_safe Logging to '/home/mysql-5.7.26/log/mysqld.log'. 2020-01-19T07:16:34.065328Z mysqld_safe Starting mysqld daemon with databases from /home/mysql-5.7.26/data
连接mysql，使用初始随机密码登陆
[root@orderer mysql-5.7.26]# mysql -uroot -p -S /home/mysql-5.7.26/mysql.sock Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 10 Server version: 5.7.26-log Copyright (c) 2000, 2019, 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>
五、修改root密码
mysql> alter user 'root'@'localhost' identified by 'xxxxxxx'; Query OK, 0 rows affected (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec) mysql>
使用新密码重新登录
[root@orderer mysql-5.7.26]# mysql -uroot -p -S /home/mysql-5.7.26/mysql.sock Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 14 Server version: 5.7.26-log Source distribution Copyright (c) 2000, 2019, 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 | | performance_schema | | sys | +--------------------+ 4 rows in set (0.01 sec) mysql>
此时，看到数据库只有mysql，接下来，我们停掉mysql服务
[root@orderer mysql-5.7.26]# mysqladmin -uroot -p -S /home/mysql-5.7.26/mysql.sock shutdown Enter password: [root@orderer mysql-5.7.26]#
六、将备份的数据文件中的数据库目录文件夹test复制到data目录下
[root@orderer mysql-5.7.26]# cp -r ../data_bak/test/ data/
查看data目录
[root@orderer mysql-5.7.26]# ll data/ ??? 110672 -rw-r----- 1 mysql mysql 56 1? 19 15:11 auto.cnf -rw------- 1 mysql mysql 1680 1? 19 15:11 ca-key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 ca.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 client-cert.pem -rw------- 1 mysql mysql 1680 1? 19 15:11 client-key.pem -rw-r----- 1 mysql mysql 356 1? 19 15:23 ib_buffer_pool -rw-r----- 1 mysql mysql 12582912 1? 19 15:23 ibdata1 -rw-r----- 1 mysql mysql 50331648 1? 19 15:23 ib_logfile0 -rw-r----- 1 mysql mysql 50331648 1? 19 15:11 ib_logfile1 -rw-r----- 1 mysql mysql 177 1? 19 15:11 master-18-69.000001 -rw-r----- 1 mysql mysql 573 1? 19 15:23 master-18-69.000002 -rw-r----- 1 mysql mysql 44 1? 19 15:16 master-18-69.index drwxr-x--- 2 mysql mysql 4096 1? 19 15:11 mysql drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 performance_schema -rw------- 1 mysql mysql 1680 1? 19 15:11 private_key.pem -rw-r--r-- 1 mysql mysql 452 1? 19 15:11 public_key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 server-cert.pem -rw------- 1 mysql mysql 1676 1? 19 15:11 server-key.pem drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 sys drwxr-x--- 2 root root 202 1? 19 15:24 test
test目录已经复制过来，因为是用root账户复制的，所以这里将文件所有者变更为mysql
[root@orderer mysql-5.7.26]# chown -R mysql:mysql data/test/ [root@orderer mysql-5.7.26]# ll data ??? 110672 -rw-r----- 1 mysql mysql 56 1? 19 15:11 auto.cnf -rw------- 1 mysql mysql 1680 1? 19 15:11 ca-key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 ca.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 client-cert.pem -rw------- 1 mysql mysql 1680 1? 19 15:11 client-key.pem -rw-r----- 1 mysql mysql 356 1? 19 15:23 ib_buffer_pool -rw-r----- 1 mysql mysql 12582912 1? 19 15:23 ibdata1 -rw-r----- 1 mysql mysql 50331648 1? 19 15:23 ib_logfile0 -rw-r----- 1 mysql mysql 50331648 1? 19 15:11 ib_logfile1 -rw-r----- 1 mysql mysql 177 1? 19 15:11 master-18-69.000001 -rw-r----- 1 mysql mysql 573 1? 19 15:23 master-18-69.000002 -rw-r----- 1 mysql mysql 44 1? 19 15:16 master-18-69.index drwxr-x--- 2 mysql mysql 4096 1? 19 15:11 mysql drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 performance_schema -rw------- 1 mysql mysql 1680 1? 19 15:11 private_key.pem -rw-r--r-- 1 mysql mysql 452 1? 19 15:11 public_key.pem -rw-r--r-- 1 mysql mysql 1112 1? 19 15:11 server-cert.pem -rw------- 1 mysql mysql 1676 1? 19 15:11 server-key.pem drwxr-x--- 2 mysql mysql 8192 1? 19 15:11 sys drwxr-x--- 2 mysql mysql 202 1? 19 15:24 test
再次启动mysql服务，并连接mysql,查看数据库
[root@orderer mysql-5.7.26]# mysql -uroot -p -S /home/mysql-5.7.26/mysql.sock Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.7.26-log Source distribution Copyright (c) 2000, 2019, 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 | | performance_schema | | sys | | test | +--------------------+ 5 rows in set (0.00 sec) mysql>
发现已经出现了test数据库，我们切换到test,并查看表
mysql> use test; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> show tables; +----------------+ | Tables_in_test | +----------------+ | t_product_item | | test | +----------------+ 2 rows in set (0.00 sec)
可以看到数据库中的表，我们查询一个表
mysql> select * from test; ERROR 1146 (42S02): Table 'test.test' doesn't exist mysql>
此时，报错，表不存在，这是因为我们没有将备份的data目录下的ibdata1文件复制过来的原因，数据库引擎使用innodb时，ibdata1文件保存了数据库元数据信息，里面保存了每个数据库里的每个表的ID
所以，我们接下来将备份的data目录下的ibdata1复制到新的数据库data目录下覆盖
七、将备份data目录下的ibdata1文件复制到新数据库data目录下并覆盖
停掉mysql
[root@orderer mysql-5.7.26]# mysqladmin -uroot -p -S /home/mysql-5.7.26/mysql.sock shutdown Enter password: [root@orderer mysql-5.7.26]#
复制备份data目录下的ibdata1文件到数据库data目录下，提示是否覆盖，输入y
[root@orderer mysql-5.7.26]# cp ../data_bak/ibdata1 data/ cp:????"data/ibdata1"? y [root@orderer mysql-5.7.26]#
我们再次启动mysql，并连接mysql
[root@orderer home]# mysqld_safe --defaults-file=/etc/mysql/my.cnf 2020-01-19T07:36:22.526939Z mysqld_safe Logging to '/home/mysql-5.7.26/log/mysqld.log'. 2020-01-19T07:36:22.574112Z mysqld_safe Starting mysqld daemon with databases from /home/mysql-5.7.26/data
[root@orderer mysql-5.7.26]# mysql -uroot -p -S /home/mysql-5.7.26/mysql.sock Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.7.26-log Source distribution Copyright (c) 2000, 2019, 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.
打开test数据库，并查看表
mysql> use test; Database changed mysql> show tables; +----------------+ | Tables_in_test | +----------------+ | t_product_item | | test | +----------------+ 2 rows in set (0.00 sec) mysql>
再查询test表
mysql> select * from test; +------+--------+ | id | name | +------+--------+ | 1 | aaaaa | | 2 | bbbb | | 3 | ccccc | | 4 | dddddd | | 5 | eeeeee | | 6 | fffff | | 7 | rrrrr | | 8 | uuuuuu | | 10 | eerrrr | +------+--------+ 9 rows in set (0.00 sec) mysql>
数据库可以正常读取了，我们再插入一条数据
mysql> insert into test values(11,'hhhhhh'); Query OK, 1 row affected (0.03 sec)
成功，查询
mysql> select * from test; +------+--------+ | id | name | +------+--------+ | 1 | aaaaa | | 2 | bbbb | | 3 | ccccc | | 4 | dddddd | | 5 | eeeeee | | 6 | fffff | | 7 | rrrrr | | 8 | uuuuuu | | 10 | eerrrr | | 11 | hhhhhh | +------+--------+ 10 rows in set (0.00 sec) mysql>
可以正常读写，至此数据文件恢复数据完成。