阿里云RDS同步到本地自建mysql数据库从库

• RDS mysql版本为5.6.29 x86_64

1、下载数据备份、binlog备份

• 内网中转？数据量不大，直接下载
• 下载数据备份(外网下载链接) wget -c "https://rdslog-st.oss-cn-shenzhen.aliyuncs.com/xxx" -O xxx.tar.gz

2、内网测试机安装mysql5.6

• wget -c "http://cdn.mysql.com//Downloads/MySQL-5.6/mysql-5.6.33-linux-glibc2.5-x86_64.tar.gz"
  tar xf mysql-5.6.-linux-glibc2.-x86_64.tar.gz -C /usr/local/
  cd /usr/local && ln -s mysql-5.6.-linux-glibc2.-x86_64 mysql
  mkdir -p /home/mysql/data
  chown -R mysql.mysql /home/mysql && chmod -R o=--- /home/mysql

3、恢复备份到内网测试机

• 下载解压脚本 rds_backup_extract.sh
• 下载恢复工具 Percona-XtraBackup

• sh rds_backup_extract.sh -f hins1438123_xtra_20160912032142.tar.gz -C /home/mysql/data
  /home/backup/percona-xtrabackup-2.4.-Linux-x86_64/bin/innobackupex --defaults-file=/home/mysql/data/backup-my.cnf --apply-log /home/mysql/data

• 编辑mysql配置文件，开启gtid

cd /home/mysql/data
cp backup-my.cnf slave-my.cnf
vim slave-my.cnf
[mysqld]
# from rds backup-my.cnf
innodb_checksum_algorithm=innodb
innodb_data_file_path=ibdata1:200M:autoextend
innodb_log_files_in_group=2
innodb_log_file_size=524288000
innodb_undo_directory=.
innodb_undo_tablespaces=0
# need for slave
server-id = 17
master-info-repository = file
relay-log-info_repository = file
binlog-format = ROW
gtid-mode = ON
enforce-gtid-consistency = true
log-bin = hostname-bin
relay-log = hostname-relay-bin
log-slave-updates

• 启动mysqld

/usr/local/mysql/bin/mysqld_safe --defaults-file=/home/mysql/data/slave-my.cnf --user=mysql --basedir=/usr/local/mysql --datadir=/home/mysql/data &

• 清除slave信息

sql> reset slave;
# 报错
ERROR 1794 (HY000): Slave is not configured or failed to initialize properly. You must at least set --server-id to enable either a master or a slave. Additional error messages can be found in the MySQL error log.
# 原因是由于RDS的备份文件中包含了RDS的主从复制关系，需要把这些主从复制关系清理掉，清理方法：
sql> truncate table mysql.slave_relay_log_info;
sql> truncate table mysql.slave_master_info;
# 然后重启服务
/usr/local/mysql/bin/mysqladmin -S /tmp/mysql.sock -uroot shutdown 

• 恢复完成的mysql.user 是不包含rds中创建的用户的，需要重新创建
• 重建用户前先执行一下sql

delete from mysql.db where user<>'root' and char_length(user)>0;
delete from mysql.tables_priv where user<>'root' and char_length(user)>0;
flush privileges;

4、配置主从同步

• 尝试 master_auto_position=1 让主从自行寻找开始复制的pos

sql> change master to
master_host=’rdsxfjwiofjwofe.mysql.rds.aliyuncs.com’,
master_user=’user_name’,master_port=3306,master_password=’xxxxx’,
master_auto_position=1;
# 结果 start slave 报错
Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'

• 上面的报错有两种解决方法：
  • 设置 master_auto_position=0 并指定 binlog 文件和 pos 位置开始复制

# binlog pos 可以从恢复的备份文件中获得

cat xtrabackup_slave_filename_info
CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000348', MASTER_LOG_POS='5569205'

　　

# 配置复制 

sql> change master to
master_host=’rdsxdjsfiwfojief.mysql.rds.aliyuncs.com’,
master_user=’user_name’,master_port=3306,master_password=’xxxxx’,
master_auto_position=0,master_log_file='mysql-bin.000348',master_log_pos=5569205;
sql> start slave;

# 可以正常开始复制，但重新设置 master_auto_position=1 又会报同样的错

* 手工修改 GTID_PURGED 值

# 同样的备份文件里有信息

cat /home/mysql/data/xtrabackup_slave_info
SET GLOBAL gtid_purged='016ced19-9d47-11e5-8f1b-1051721bd1ff:1-1875724, 068bb241-3474-11e6-a8e5-8038bc0c695e:1-1858400, 0e1a732e-9d47-11e5-8f1b-d89d672b932c:1-4';
CHANGE MASTER TO MASTER_AUTO_POSITION=

# 配置主从

sql> change master to

master_host=’rdsxfslfiewfiewfji.mysql.rds.aliyuncs.com’,

master_user=’user_name’,master_port=3306,master_password=’xxxxx’,
master_auto_position=1;
sql> start slave; # 报错
sql> stop slave;
sql> reset master;
sql> SET GLOBAL gtid_purged='016ced19-9d47-11e5-8f1b-1051721bd1ff:1-1875724, 068bb241-3474-11e6-a8e5-8038bc0c695e:1-1858400, 0e1a732e-9d47-11e5-8f1b-d89d672b932c:1-4';
sql> start slave;

5、最后看下slave状态
一开始 Seconds_Behind_Master 值会很大，是因为使用的数据备份是前一天的，等它慢慢同步完就正常了

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: rdsxxxxxxxxxxxxx.mysql.rds.aliyuncs.com
                  Master_User: user_name
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000350
          Read_Master_Log_Pos: 1717466
               Relay_Log_File: hostname-relay-bin.000006
                Relay_Log_Pos: 1717596
        Relay_Master_Log_File: mysql-bin.000350
             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: 1717466
              Relay_Log_Space: 1717886
              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: 2224019206
                  Master_UUID: 068bb241-3474-11e6-a8e5-8038bc0c695e
             Master_Info_File: /home/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set: 068bb241-3474-11e6-a8e5-8038bc0c695e:1858401-1875134
            Executed_Gtid_Set: 016ced19-9d47-11e5-8f1b-1051721bd1ff:1-1875724,
068bb241-3474-11e6-a8e5-8038bc0c695e:1-1875134,
0e1a732e-9d47-11e5-8f1b-d89d672b932c:1-4
                Auto_Position: 1
1 row in set (0.00 sec)

ERROR:
No query specified

mysql>

作者：Eraz
链接：https://www.jianshu.com/p/4582db124579
來源：简书
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