使用innobackupex基于从库搭建mysql主从架构
现有的架构是一主一从，版本为Mysql5.6.37。实施要求是：利用从库，搭建第二个从库，版本为5.7.21
1、备份从库1
[root@mysql02 ~]./innobackupex --user=root --password="xxxxxx" --slave-info --safe-slave-backup --parallel=3 /data/backup/
#复制my.cnf文件到新从库
[root@mysql02 ~]$scp /etc/my.cnf 192.168.1.23:/data/backup
2、主库授予从库2复制账户
master@MySQL> grant replication slave,replication client on *.* to repl@'192.168.1.23' identified by 'repl';
3、从库2：进行恢复
[root@mysql03 ~]$./innobackupex --user=root --password="xxxxxx" --apply-log --use-memory=2G /data/backup/2018-08-10_17-29-01
[root@mysql03 ~]$mv /data/backup/2018-08-10_17-29-01 /data/mysql_3306
4、准备从库2配置文件my.cnf,根据需要修改相应参数，这里的修改如下，
skip-slave-start
datadir = /data/mysql_3306
port = 3306
server_id = 330623
socket = /data/mysql_3306/mysql.sock
pid-file=/data/mysql_3306/mysql3307.pid
log_error=/data/mysql_3306/mysql_error.log
5、启动从库2
# chown -R mysql:mysql /data/backup
# mysqld_safe --defaults-file=/etc/my.cnf &
6、运行mysql时，提示Table ‘performance_schema.session_variables’ doesn’t exist
./mysql_upgrade -hlocalhost -u root -p --force -P3306 sock=/data/mysql_3306/mysql.sock
重启数据库
7、change master
mysql> system more /log/recover/xtrabackup_slave_info
CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000658', MASTER_LOG_POS=925384099
mysql> CHANGE MASTER TO
-> MASTER_HOST='192.168.1.21',
-> MASTER_USER='repl',
-> MASTER_PASSWORD='repl',
-> MASTER_PORT=3306,
-> MASTER_LOG_FILE='mysql-bin.000658',
-> MASTER_LOG_POS=925384099;
Query OK, 0 rows affected, 2 warnings (0.31 sec)
mysql> start slave;
在从库2，start slave时报：error:
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.
经分析，需要：
删除5张表，并重新导入脚本
use mysql
drop table slave_master_info;
drop table slave_relay_log_info;
drop table slave_worker_info;
drop table innodb_index_stats;
drop table innodb_table_stats;
检查表数据，为空表，重建表
source /backup/mysql_system_tables.sql
(2)重新启动数据库
mysql> start slave;
mysql> show slave status\G;