GTID模式下切换的时候，默认是不会去Master上获取binlog，如果配置了Binlog Server，MHA机会去binlog-server上获取，下面创建一个binlog server，并验证binlog server能够在主库binlog被清理的情况下提供日志恢复.

搭建binlog_server

创建目录：创建binlog_server用于存放master上的binlog

[root@mha2 binlog_server]# mkdir binlog_server
[root@mha2 binlog_server]# pwd
/export/binlog_server

开启远程备份binlog

nohup mysqlbinlog --no-defaults --read-from-remote-server --raw --result-file=/export/binlog_server/ --host=192.168.10.129 --port=3358 --user=mha --password=abcd1234 --stop-never mysql-bin.000079 &

--raw: 以原始格式输出，而不是解析为SQL语句

--result-file： 本地路径，用于保存binlog

--user=mha: mysql账户，用于连接mysql并备份binlog，需要有replication cilent权限

--stop-never： 不停

mysql-bin.000060： 在master上第一个binlog，从这个binlog开始向后备份

更新配置：配置中添加了[binlog1] 部分，且[server2]添加了no_master=1

binlog server和master不要放在同一个机器，否则主库挂了同时binlog server也挂了；

[server default]
manager_workdir=/export/mha/app1
manager_log=/export/mha/app1/manager.log
master_binlog_dir=/export/data/mysql
log_level=debug
user=mha
password=abcd1234
ping_interval=3
ping_type=INSERT
remote_workdir=/export/mha/app1
ssh_user=root
repl_user=repl
repl_password=abcd1234[server1]
hostname=192.168.10.129
candidate_master=1
port=3358
master_binlog_dir=/export/data/mysql[server2]
no_master=1
hostname=192.168.10.163
port=3358
master_binlog_dir=/export/data/mysql[server3]
hostname=192.168.10.162
port=3358
master_binlog_dir=/export/data/mysql[binlog1]
hostname=192.168.10.163
master_binlog_dir=/export/binlog_server

查看同步

查看master中的binlog和binlog_server中对比，是否获取了最新的binlog，切master flush的时候从库也会同步更新.

# master
mysql> show master logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000079 |      3699 |
| mysql-bin.000080 |       257 |
| mysql-bin.000081 |       234 |
+------------------+-----------+
3 rows in set (0.00 sec)# slave
[root@mha2 binlog_server]# ls
mysql-bin.000079  mysql-bin.000080  mysql-bin.000081 

模拟故障

1，slave： stop slave io_thread

2， 开启MHA

3， master: 执行一些事务

mysql> insert into hero3(name,age) values(name,age);
Query OK, 1 row affected (0.03 sec)mysql> flush logs;
Query OK, 0 rows affected (0.01 sec)mysql> insert into hero3(name,age) values(name,age);
Query OK, 1 row affected (0.00 sec)mysql> flush logs;
Query OK, 0 rows affected (0.00 sec)mysql> show master logs;
+------------------+-----------+
| Log_name         | File_size |
+------------------+-----------+
| mysql-bin.000079 |      3699 |
| mysql-bin.000080 |       257 |
| mysql-bin.000081 |    123737 |
| mysql-bin.000082 |     89801 |
| mysql-bin.000083 |       281 |
| mysql-bin.000084 |      2667 |
| mysql-bin.000085 |       546 |
| mysql-bin.000086 |       234 |
+------------------+-----------+
8 rows in set (0.00 sec)

4， 查看主从数据差异

# master
mysql> select count(1) from hero3;
+----------+
| count(1) |
+----------+
|     7170 |
+----------+
1 row in set (0.01 sec)# slave:
mysql> select count(1) from hero3;
+----------+
| count(1) |
+----------+
|     7168 |
+----------+
1 row in set (0.02 sec)

5, 清理主库所有binlog

mysql> purge binary logs to 'mysql-bin.000086';
Query OK, 0 rows affected (0.00 sec)

6， 将主库关闭实例

此时触发故障切换

7， 查看新主从上的数据，同步了刚刚丢失的数据

mysql> select count(1) from hero3;
+----------+
| count(1) |
+----------+
|     7170 |
+----------+
1 row in set (0.00 sec)

8，查看切换日志

From:
192.168.10.129(192.168.10.129:3358) (current master)+--192.168.10.163(192.168.10.163:3358)+--192.168.10.162(192.168.10.162:3358)To:
192.168.10.162(192.168.10.162:3358) (new master)+--192.168.10.163(192.168.10.163:3358)
on Dec 23 23:58:36 2024 - [info] Fetching binary logs from binlog server 192.168.10.163..
Mon Dec 23 23:58:36 2024 - [info] Executing binlog save command: save_binary_logs --command=save --start_file=mysql-bin.000082  --start_pos=89047 --output_file=/export/mha/app1/saved_binlog_binlog1_20241223235834.binlog --handle_raw_binlog=0 --skip_filter=1 --disable_log_bin=0 --manager_version=0.58 --oldest_version=5.7.19-log  --debug  --binlog_dir=/export/binlog_server Creating /export/mha/app1 if not exists..    ok.Concat binary/relay logs from mysql-bin.000082 pos 89047 to mysql-bin.000086 EOF into /export/mha/app1/saved_binlog_binlog1_20241223235834.binlog ..
Executing command: mysqlbinlog --start-position=89047  /export/binlog_server/mysql-bin.000082 >> /export/mha/app1/saved_binlog_binlog1_20241223235834.binlog
Executing command: mysqlbinlog --start-position=4  /export/binlog_server/mysql-bin.000083 >> /export/mha/app1/saved_binlog_binlog1_20241223235834.binlog
Executing command: mysqlbinlog --start-position=4  /export/binlog_server/mysql-bin.000084 >> /export/mha/app1/saved_binlog_binlog1_20241223235834.binlog
Executing command: mysqlbinlog --start-position=4  /export/binlog_server/mysql-bin.000085 >> /export/mha/app1/saved_binlog_binlog1_20241223235834.binlog
Executing command: mysqlbinlog --start-position=4  /export/binlog_server/mysql-bin.000086 >> /export/mha/app1/saved_binlog_binlog1_20241223235834.binlogConcat succeeded.
Mon Dec 23 23:58:37 2024 - [info] scp from root@192.168.10.163:/export/mha/app1/saved_binlog_binlog1_20241223235834.binlog to local:/export/mha/app1/saved_binlog_192.168.10.163_binlog1_20241223235834.binlog succeeded.
Mon Dec 23 23:58:37 2024 - [info] End of log messages from 192.168.10.163.
Mon Dec 23 23:58:37 2024 - [info] Saved mysqlbinlog size from 192.168.10.163 is 134787 bytes.
Mon Dec 23 23:58:37 2024 - [info] Checking if super_read_only is defined and turned on..
Mon Dec 23 23:58:37 2024 - [info]  not present or turned off, ignoring.
Mon Dec 23 23:58:37 2024 - [info] Applying differential binlog /export/mha/app1/saved_binlog_192.168.10.163_binlog1_20241223235834.binlog ..
Mon Dec 23 23:58:38 2024 - [info] Differential log apply from binlog server succeeded.
Mon Dec 23 23:58:38 2024 - [info] Getting new master's binlog name and position..

日志中可以看到去访问binlog，获取binlog，并应用binlog