利用binlog server及Xtrabackup备份集来恢复误删表（drop）

 

Preface

 

    Today I'm gonna test how to rescue a dropped table from binlog server based on a full Xtrabackup backup set.

 

Framework

 

Hostname	IP/Port	Identity	OS Version	MySQL Version	GTID Mode	Binlog Format
zlm1	192.168.56.100/3306	master	CentOS 7.0	5.7.21	on	row
zlm2	192.168.56.101/3306	slave	CentOS 7.0	5.7.21	on	row
zlm3	192.168.56.102/3306	binlog server	CentOS 7.0	5.7.21	on	row

 

Precedure

 

Step 1: Create binlog server.

 

Check the position on master 

 zlm@192.168.56.100: [sysbench]>show master status;
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                               |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | mysql-bin. |       |              |                  | 2a4b3562-2ab6-11e8-be7a-080027de0e0e:- |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
  row in set (0.00 sec)

Make binlog server begin to receive binlog.

 [root@zlm3 :: /data]
 #mysqlbinlog -R --raw -h192.168.56. -urepl -prepl4slave -P3306 --stop-never mysql-bin. &
 []
 mysqlbinlog: [Warning] Using a password on the command line interface can be insecure.

 [root@zlm3 :: /data]
 #ls -l
 total
 drwxr-xr-x  mysql mysql   Jun  : backup
 drwxr-xr-x  mysql mysql   Mar  : mysql
 -rw-r-----  root  root   Jul  : mysql-bin.

Flush two logs on master.

 zlm@192.168.56.100: [sysbench]>flush logs;
 Query OK,  rows affected (0.06 sec)

 zlm@192.168.56.100: [sysbench]>flush logs;
 Query OK,  rows affected (0.01 sec)

 zlm@192.168.56.100: [sysbench]>show master status;
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                               |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | mysql-bin. |       |              |                  | 2a4b3562-2ab6-11e8-be7a-080027de0e0e:- |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
  row in set (0.00 sec)

Check whether the newly generated binlogs are successfully transmited to binlog server.

 [root@zlm3 :: /data]
 #ls -l
 total
 drwxr-xr-x  mysql mysql   Jun  : backup
 drwxr-xr-x  mysql mysql   Mar  : mysql
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.

Step 2: Destroy the table.

 

Check target table on master.

 zlm@192.168.56.100: [sysbench]>show tables;
 +--------------------+
 | Tables_in_sysbench |
 +--------------------+
 | sbtest1            |
 | sbtest2            |
 | sbtest3            |
 | sbtest4            |
 | sbtest5            |
 | sbtest6            |
 +--------------------+
  rows in set (0.00 sec)

 zlm@192.168.56.100: [sysbench]>select count(*) from sbtest6;
 +----------+
 | count(*) |
 +----------+
 |         |
 +----------+
  row in set (0.00 sec)

 zlm@192.168.56.100: [sysbench]>insert into sbtest6 values(,,'a','b');
 Query OK,  row affected (0.00 sec)

 zlm@192.168.56.100: [sysbench]>select * from sbtest6;
 +----+---+---+-----+
 | id | k | c | pad |
 +----+---+---+-----+
 |   |  | a | b   |
 +----+---+---+-----+
  row in set (0.00 sec)

Generate Xtrabackup backup set.

 [root@zlm1 :: ~]
 #innobackupex --defaults-file=/data/mysql/mysql3306/my3306.cnf -uroot -pPassw0rd /data/backup
  :: innobackupex: Error: extra argument found -pPassw0rd
  :: innobackupex: Error: extra argument found /data/backup

 [root@zlm1 :: ~]
 #innobackupex -v
 innobackupex version 2.4. Linux (x86_64) (revision id: df58cf2)

 [root@zlm1 :: ~]
 #innobackupex --defaults-file=/data/mysql/mysql3306/my3306.cnf --user=root --password=Passw0rd /data/backup
  :: innobackupex: Starting the backup operation
 ...

  :: Backup created in directory '/data/backup/2018-07-29_16-32-33'
 MySQL binlog position: filename 'mysql-bin.000100', position '', GTID of the last change '2a4b3562-2ab6-11e8-be7a-080027de0e0e:1-12715694'
  :: [] Writing backup-my.cnf
  :: []        ...done
  :: [] Writing xtrabackup_info
  :: []        ...done
 xtrabackup: Transaction log of lsn () to () was copied.
  :: completed OK!

Insert one record of "sbtest6" and drop it.

 zlm@192.168.56.100: [sysbench]>insert into sbtest6 values(,,'c','d');
 Query OK,  row affected (0.00 sec)

 zlm@192.168.56.100: [sysbench]>show master status;
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                               |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | mysql-bin. |       |              |                  | 2a4b3562-2ab6-11e8-be7a-080027de0e0e:- |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
  row in set (0.00 sec)

 zlm@192.168.56.100: [sysbench]>drop tables sbtest6;
 Query OK,  rows affected (0.02 sec)

 zlm@192.168.56.100: [sysbench]>show master status;
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                               |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
 | mysql-bin. |       |              |                  | 2a4b3562-2ab6-11e8-be7a-080027de0e0e:- |
 +------------------+----------+--------------+------------------+-------------------------------------------------+
  row in set (0.00 sec)

Shutdown the mysqld on master(mimic the MySQL instance down).

 [root@zlm1 :: /data/backup]
 #mysqladmin shutdown

 [root@zlm1 :: /data/backup]
 #ps aux|grep mysqld
 mysql       0.0 20.7   pts/  Sl   :   : mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm1 :: /data/backup]
 #ps aux|grep mysqld
 mysql       0.0 20.1   pts/  Sl   :   : mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm1 :: /data/backup]
 #mysqladmin shutdown
 mysqladmin: connect to server at '192.168.56.100' failed
 error: 'Can't connect to MySQL server on '192.168.56.100' ()'
 Check that mysqld is running on 192.168.56.100 and that the port is .
 You can check this by doing 'telnet 192.168.56.100 3306'

 [root@zlm1 :: /data/backup]
 #ps aux|grep mysqld
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

Copy backup set to zlm2.

 [root@zlm1 :: ~]
 #cd /data/backup/

 [root@zlm1 :: /data/backup]
 #ls -l
 total
 drwxr-x---  root root  Jul  : --29_16--

 [root@zlm1 :: /data/backup]
 #scp -r --29_16-- zlm2:/data/backup
 xtrabackup_logfile                                                                                                 %      .5KB/s   :
 ibdata1                                                                                                            %  100MB  .0MB/s   :
 ... //Omitted.

Step 3: Rescue data.

 

Prepare to restore the backup with "--apply-log" on zlm2.

 [root@zlm2 :: /data/backup]
 #ls -l
 total
 drwxr-x---  root root  Jul  : --29_16--

 [root@zlm2 :: /data/backup]
 #innobackupex -v
 xtrabackup: recognized server arguments: --datadir=/var/lib/mysql
 innobackupex version 2.4. Linux (x86_64) (revision id: 170eb8c)

 [root@zlm2 :: /data/backup]
 #innobackupex --defaults-file=/data/mysql/mysql3306/my3306.cnf -uroot -pPassw0rd --apply-log /data/backup/--29_16--/
 ... //Omitted.

 xtrabackup: starting shutdown with innodb_fast_shutdown =
 InnoDB: page_cleaner: 1000ms intended loop took 8812ms. The settings might not be optimal. (flushed= and evicted=, during the time.)
 InnoDB: FTS optimize thread exiting.
 InnoDB: Starting shutdown...
 InnoDB: Shutdown completed; log sequence number
  :: completed OK!

Shutdown instance and copy back.

 [root@zlm2 :: /data/backup]
 #ps aux|grep mysqld
 mysql       0.0 18.7   pts/  Sl   :   : mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm2 :: /data/backup]
 #mysqladmin shutdown

 [root@zlm2 :: /data/backup]
 #ps aux|grep mysqld
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm2 :: /data/backup]
 #cd /data/mysql/mysql3306/data/

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #rm -rf *

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #cd ../logs

 [root@zlm2 :: /data/mysql/mysql3306/logs]
 #rm -rf *

 [root@zlm2 :: /data/mysql/mysql3306/logs]
 #innobackupex --defaults-file=/data/mysql/mysql3306/my3306.cnf -uroot -pPassw0rd --copy-back /data/backup/--29_16--/
 ... //Omitted.

Restart instance and check table.

 [root@zlm2 :: /data/mysql/mysql3306/logs]
 #cd ../data

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #chown -R mysql.mysql *

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #sh /root/mysqld.sh

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #ps aux|grep mysqld
 mysql       3.2 17.9   pts/  Sl   :   : mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm2 :: /data/mysql/mysql3306/data]
 #mysql
 Welcome to the MySQL monitor.  Commands end with ; or \g.
 Your MySQL connection id is
 Server version: 5.7.-log MySQL Community Server (GPL)

 Copyright (c) , , 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.

 zlm@192.168.56.101: [(none)]>use sysbench
 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
 zlm@192.168.56.101: [sysbench]>show tables;
 +--------------------+
 | Tables_in_sysbench |
 +--------------------+
 | sbtest1            |
 | sbtest2            |
 | sbtest3            |
 | sbtest4            |
 | sbtest5            |
 | sbtest6            |
 +--------------------+
  rows in set (0.00 sec)

 zlm@192.168.56.101: [sysbench]>select * from sbtest6;
 +----+---+---+-----+
 | id | k | c | pad |
 +----+---+---+-----+
 |   |  | a | b   |
 +----+---+---+-----+
  row in set (0.00 sec)

Step 4: Implement a slave with binlog server.

 

Start mysqld on binlog server.

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ps aux|grep mysqld
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #sh /root/mysqld.sh

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ps aux|grep mysqld
 mysql      16.5 15.6   pts/   Rl   :   : mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqld

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ls -l
 total
 -rw-r-----  root  root       Jul  : mysql-bin.
 -rw-r-----  root  root        Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  mysql mysql       Jul  : mysql-bin.
 -rw-r-----  mysql mysql        Jul  : mysql-bin.index

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #cat mysql-bin.index
 /data/mysql/mysql3306/logs/mysql-bin.

Disguise the binlog server is a fake master.

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #rm -f mysql-bin.*
 []+  Done                    mysqlbinlog -R --raw -h192.168.56. -urepl -prepl4slave -P3306 --stop-never mysql-bin.  (wd: /data)
 (wd now: /data/mysql/mysql3306/logs)

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ls -l
 total
 -rw-r-----  mysql mysql  Jul  : mysql-bin.index

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ps aux|grep mysqlbinlog
 root        0.0  0.0     pts/    R+   :   : grep --color=auto mysqlbinlog

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #cp /data/mysql-bin* .

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ls -l
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.
 -rw-r-----  root  root   Jul  : mysql-bin.index

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ls - | awk '{print i$0}' i=`pwd`'/'|grep mysql-bin. > mysql-bin.index

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #cat mysql-bin.index
 /data/mysql/mysql3306/logs/mysql-bin.
 /data/mysql/mysql3306/logs/mysql-bin.
 /data/mysql/mysql3306/logs/mysql-bin.

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #chown mysql.mysql *

 [root@zlm3 :: /data/mysql/mysql3306/logs]
 #ls -l
 total
 -rw-r-----  mysql mysql  Jul  : mysql-bin.
 -rw-r-----  mysql mysql  Jul  : mysql-bin.
 -rw-r-----  mysql mysql  Jul  : mysql-bin.
 -rw-r-----  mysql mysql  Jul  : mysql-bin.index

Change the server-uuid of binlog server to be equal with master.

 [root@zlm3 :: /data/mysql/mysql3306]
 #cd ../data

 [root@zlm3 :: /data/mysql/mysql3306/data]
 #cat auto.cnf
 [auto]
 server-uuid=e00ef9f5-6c4b-11e8--080027de0e0e

 [root@zlm3 :: /data/mysql/mysql3306/data]
 #vim auto.cnf

 [root@zlm3 :: /data/mysql/mysql3306/data]
 #cat auto.cnf
 [auto]
 server-uuid=2a4b3562-2ab6-11e8-be7a-080027de0e0e

Execute "change master to ... " on zlm2.

 zlm@192.168.56.101: [sysbench]>change master to \
     -> master_host='192.168.56.102',\
     -> master_port=,\
     -> master_user='repl',\
     -> master_password='repl4slave',\
     -> master_auto_position=;
 Query OK,  rows affected,  warnings (0.01 sec)

Start IO_Thread on zlm2.

 [root@zlm2 :: /data/backup/--29_16--]
 #cat xtrabackup_binlog_info
 mysql-bin.        2a4b3562-2ab6-11e8-be7a-080027de0e0e:-

 zlm@192.168.56.101: [sysbench]>reset master;
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [sysbench]>set @@global.gtid_purged='2a4b3562-2ab6-11e8-be7a-080027de0e0e:1-12715694';
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [sysbench]>start slave io_thread;
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [sysbench]>show slave status\G
 *************************** . row ***************************
                Slave_IO_State:
                   Master_Host: 192.168.56.102
                   Master_User: repl
                   Master_Port:
                 Connect_Retry:
               Master_Log_File:
           Read_Master_Log_Pos:
                Relay_Log_File: relay-bin.
                 Relay_Log_Pos:
         Relay_Master_Log_File:
              Slave_IO_Running: No
             Slave_SQL_Running: No
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno:
                    Last_Error:
                  Skip_Counter:
           Exec_Master_Log_Pos:
               Relay_Log_Space:
               Until_Condition: None
                Until_Log_File:
                 Until_Log_Pos:
            Master_SSL_Allowed: No
            Master_SSL_CA_File:
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master: NULL
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno:
                 Last_IO_Error: Got fatal error  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.'
                Last_SQL_Errno:
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id:
                   Master_UUID: e00ef9f5-6c4b-11e8--080027de0e0e
              Master_Info_File: /data/mysql/mysql3306/data/master.info
                     SQL_Delay:
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State:
            Master_Retry_Count:
                   Master_Bind:
       Last_IO_Error_Timestamp:  ::
      Last_SQL_Error_Timestamp:
                Master_SSL_Crl:
            Master_SSL_Crlpath:
            Retrieved_Gtid_Set:
             Executed_Gtid_Set: 2a4b3562-2ab6-11e8-be7a-080027de0e0e:-
                 Auto_Position:
          Replicate_Rewrite_DB:
                  Channel_Name:
            Master_TLS_Version:
  row in set (0.00 sec)

    I was stucked here.Slave IO_Thread could not be started with 1236,although I had replaced the server-uuid and set the variable of gtid_purged.Only if the slave get binlog which contains the incremental data and start the slave SQL_Thread.We can get back our dropped table together with the modification on it.

 

Supplemented on July 31:

 

    The previous fault of 1236 was due to the wrong configuration of variable "gtid_purged".There were two individual gtids generated by the other masters with different uuid as bellow:

 

 

 

    Therefore,the configuration command should be executed like this:

 

 set @@global.gtid_purged='27af30ca-6800-11e8-ad7e-080027de0e0e:1,
 2a4b3562-2ab6-11e8-be7a-080027de0e0e:-,
 e00ef9f5-6c4b-11e8--080027de0e0e:';

    not merely set it like this:

 

 set @@global.gtid_purged='2a4b3562-2ab6-11e8-be7a-080027de0e0e:1-12715694';

    Eventually,In order to make the gtid more clear,I executed "reset master" on binlog server(zlm3) and then copyed those necessary binlogs which were transfered from original master.Further more,I changed back the uuid of zlm3.Because I found that there's no need to change it at all.

    The new procedure of demonstration was shown below:

 

 zlm@192.168.56.101: [(none)]>set @@global.gtid_purged='2a4b3562-2ab6-11e8-be7a-080027de0e0e:1-12715694';
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [(none)]>change master to master_host='192.168.56.102',master_port=,master_user='repl',master_password='repl4slave',master_auto_position=;
 Query OK,  rows affected,  warnings (0.01 sec)

 zlm@192.168.56.101: [(none)]>start slave io_thread;
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [(none)]>show slave status\G
 *************************** . row ***************************
                Slave_IO_State: Waiting for master to send event
                   Master_Host: 192.168.56.102
                   Master_User: repl
                   Master_Port:
                 Connect_Retry:
               Master_Log_File: mysql-bin.
           Read_Master_Log_Pos:
                Relay_Log_File: relay-bin.
                 Relay_Log_Pos:
         Relay_Master_Log_File:
              Slave_IO_Running: Yes
             Slave_SQL_Running: No
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno:
                    Last_Error:
                  Skip_Counter:
           Exec_Master_Log_Pos:
               Relay_Log_Space:
               Until_Condition: None
                Until_Log_File:
                 Until_Log_Pos:
            Master_SSL_Allowed: No
            Master_SSL_CA_File:
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master: NULL
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno:
                 Last_IO_Error:
                Last_SQL_Errno:
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id:
                   Master_UUID: e00ef9f5-6c4b-11e8--080027de0e0e //I changed back the uuid of zlm3 to its previous value.
              Master_Info_File: /data/mysql/mysql3306/data/master.info
                     SQL_Delay:
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State:
            Master_Retry_Count:
                   Master_Bind:
       Last_IO_Error_Timestamp:
      Last_SQL_Error_Timestamp:
                Master_SSL_Crl:
            Master_SSL_Crlpath:
            Retrieved_Gtid_Set: 2a4b3562-2ab6-11e8-be7a-080027de0e0e:- //New gtid was received.
             Executed_Gtid_Set: 2a4b3562-2ab6-11e8-be7a-080027de0e0e:-
                 Auto_Position:
          Replicate_Rewrite_DB:
                  Channel_Name:
            Master_TLS_Version:
  row in set (0.00 sec)

 zlm@192.168.56.101: [sysbench]>start slave sql_thread until sql_before_gtids='2a4b3562-2ab6-11e8-be7a-080027de0e0e:12715696';
 Query OK,  rows affected (0.00 sec)

 zlm@192.168.56.101: [sysbench]>show slave status\G
 *************************** . row ***************************
                Slave_IO_State: Waiting for master to send event
                   Master_Host: 192.168.56.102
                   Master_User: repl
                   Master_Port:
                 Connect_Retry:
               Master_Log_File: mysql-bin.
           Read_Master_Log_Pos:
                Relay_Log_File: relay-bin.
                 Relay_Log_Pos:
         Relay_Master_Log_File: mysql-bin.
              Slave_IO_Running: Yes
             Slave_SQL_Running: No
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno:
                    Last_Error:
                  Skip_Counter:
           Exec_Master_Log_Pos:
               Relay_Log_Space:
               Until_Condition: SQL_BEFORE_GTIDS
                Until_Log_File:
                 Until_Log_Pos:
            Master_SSL_Allowed: No
            Master_SSL_CA_File:
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master: NULL
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno:
                 Last_IO_Error:
                Last_SQL_Errno:
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id:
                   Master_UUID: e00ef9f5-6c4b-11e8--080027de0e0e
              Master_Info_File: /data/mysql/mysql3306/data/master.info
                     SQL_Delay:
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State:
            Master_Retry_Count:
                   Master_Bind:
       Last_IO_Error_Timestamp:
      Last_SQL_Error_Timestamp:
                Master_SSL_Crl:
            Master_SSL_Crlpath:
            Retrieved_Gtid_Set: 2a4b3562-2ab6-11e8-be7a-080027de0e0e:-
             Executed_Gtid_Set: 2a4b3562-2ab6-11e8-be7a-080027de0e0e:-
                 Auto_Position:
          Replicate_Rewrite_DB:
                  Channel_Name:
            Master_TLS_Version:
  row in set (0.00 sec)

 zlm@192.168.56.101: [sysbench]>select * from sbtest6;
 +----+---+---+-----+
 | id | k | c | pad |
 +----+---+---+-----+
 |   |  | a | b   |
 |   |  | c | d   |
 +----+---+---+-----+
  rows in set (0.00 sec)

 //The incremental data in "sbtest6" had been come again.It was okay this time.

Summary

• Binlog server act as a master in this experiment.It can prevent data loss such as miss opeartion of dropping tables whenever the master crashes.
• We can implement as many binlog servers as possible to continuously acquire the binlogs on different masters.
• If the only purpose is to get back the dropping data,replication filter of "replicate_do_table" is not necessary.
• The modification of "sever-uuid" is also neglectable operation.Each gtid contains a differten uuid is completely acceptable.It won't influence our replication except for a little bit complex in output.