mysql> GRANT REPLICATION SLAVE ON *.* TO ‘repl’@’%’;
Query OK, 0 rows affected (0.01 sec)

# 步骤2：在主库上查看binlog位置
mysql> SHOW MASTER STATUS;
+——————+———-+————–+——————+——————-+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+——————+———-+————–+——————+——————-+
| mysql-bin.000001 | 12345 | | | |
+——————+———-+————–+——————+——————-+

# 步骤3：在从库上配置主从复制
mysql> CHANGE MASTER TO
-> MASTER_HOST=’pc-12345678.mysql.polardb.rds.aliyuncs.com’,
-> MASTER_USER=’repl’,
-> MASTER_PASSWORD=’password’,
-> MASTER_LOG_FILE=’mysql-bin.000001′,
-> MASTER_LOG_POS=12345;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

# 步骤4：启动从库复制
mysql> START SLAVE;
Query OK, 0 rows affected (0.01 sec)

# 步骤5：查看从库状态
mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: pc-12345678.mysql.polardb.rds.aliyuncs.com
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 12345
Relay_Log_File: relay-bin.000001
Relay_Log_Pos: 12345
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 12345
Relay_Log_Space: 12345
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: 12345678-1234-1234-1234-1234567890ab
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

# 测试主从复制
# 在主库上插入数据
mysql> INSERT INTO fgedudb.fgedu_user (name, age, email) VALUES (‘test4’, 23, ‘test4@example.com’);
Query OK, 1 row affected (0.01 sec)

# 在从库上查看数据
mysql> SELECT * FROM fgedudb.fgedu_user;
+—-+——-+—–+——————+
| id | name | age | email |
+—-+——-+—–+——————+
| 1 | test1 | 20 | test1@example.com |
| 2 | test2 | 21 | test2@example.com |
| 3 | test3 | 22 | test3@example.com |
| 4 | test4 | 23 | test4@example.com |
+—-+——-+—–+——————+

# 步骤1：检测灾难
# 通过监控系统发现主库所在数据中心故障

# 步骤2：评估影响
# 主库不可用，业务无法正常运行

# 步骤3：启动灾难恢复计划
# 切换到异地备份实例

# 步骤4：执行恢复
# 使用阿里云CLI恢复备份
$ aliyun polardb RestoreDBCluster \
–DBClusterId “pc-12345678” \
–RestoreTime “2026-03-31T10:00:00Z” \
–RestoreType “Backup”

# 查看恢复状态
$ aliyun polardb DescribeDBClusters \
–DBClusterId “pc-12345678”

# 步骤5：验证恢复
# 登录新实例，验证数据是否完整
$ mysql -u fgedu -p -h pc-12345678.mysql.polardb.rds.aliyuncs.com -P 3306 -e “SELECT * FROM fgedudb.fgedu_user;”
Enter password:
+—-+——-+—–+——————+
| id | name | age | email |
+—-+——-+—–+——————+
| 1 | test1 | 20 | test1@example.com |
| 2 | test2 | 21 | test2@example.com |
| 3 | test3 | 22 | test3@example.com |
| 4 | test4 | 23 | test4@example.com |
+—-+——-+—–+——————+

# 步骤6：恢复服务
# 更新应用配置，将数据库连接地址改为新实例的地址
# 启动业务服务

# 步骤1：检测主库故障
# 通过监控系统发现主库故障

# 步骤2：验证主库故障
# 尝试连接主库，确认主库不可用
$ mysql -u fgedu -p -h pc-12345678.mysql.polardb.rds.aliyuncs.com -P 3306 -e “SELECT 1;”
Enter password:
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2003 (HY000): Can’t connect to MySQL server on ‘pc-12345678.mysql.polardb.rds.aliyuncs.com’ (111)

# 步骤3：检查从库状态
# 确认从库复制正常，数据同步完成
mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: pc-12345678.mysql.polardb.rds.aliyuncs.com
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 23456
Relay_Log_File: relay-bin.000001
Relay_Log_Pos: 23456
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: No
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 23456
Relay_Log_Space: 23456
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 1045
Last_IO_Error: error connecting to master ‘repl@pc-12345678.mysql.polardb.rds.aliyuncs.com:3306’: Authentication plugin ‘caching_sha2_password’ reported error: Authentication requires secure connection.
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: 12345678-1234-1234-1234-1234567890ab
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

# 步骤4：将从库提升为主库
mysql> STOP SLAVE;
Query OK, 0 rows affected (0.01 sec)

mysql> RESET SLAVE ALL;
Query OK, 0 rows affected (0.01 sec)

# 步骤5：更新应用配置
# 将应用的数据库连接地址改为从库的地址

# 步骤6：验证应用服务
# 启动应用服务，验证服务是否正常运行