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From:Sashan Govender Date:February 21 2011 11:58pm
Subject:RE: replication after network link failure
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I've done some further investigation and in summary when the break in the link between the
two networks isn't directly at one of the mysql db hosts then replication doesn't happen
instantly after the link is restored.

Case 1:

mysqldb1 ------- switch ---- broken link --- router ----- switch ------- mysqldb2.

In this case when the link is restored replication isn't instantaneous and I need to
manually intervene with a slave start;slave stop; to get data to replicate.

Case 2:

mysqldb1 --- broken link --- switch --- router ---- switch ---- mysqldb2

In this case replication is instantaneous. I don't need to manually intervene.


What's the recommended way to handle case 1?




________________________________
From: vegivamp@stripped [mailto:vegivamp@stripped] On Behalf Of Johan De Meersman
Sent: Monday, February 21, 2011 10:56 PM
To: Govender, Sashan
Cc: replication@stripped
Subject: Re: replication after network link failure

Very peculiar indeed. Does the master's 'show master status'output line up with the
slave's 'show slave status' output ?

On Mon, Feb 21, 2011 at 2:37 AM, Govender, Sashan
<Sashan.Govender@stripped<mailto:Sashan.Govender@stripped>> wrote:
Hi

We have an issue with replication where data in the table is not replicated within 5
minutes after network link fails. The setup we have is a master/master. We have an
application writing to node 1 and the data is replicated to node 2. Then we pull out the
cable connecting the 2 nodes while the application is writing to the database. After a
while we stick the cable back in and check node 2 expecting that the data is replicated
there but it isn't. There are no errors in the log file to indicate anything wrong.

The output from show slave status\G looks sane after plugging the cable back into the
switch. I've pasted the output from both nodes below. There are no errors in the mysql
log files but the data that I expect to be replicated after plugging the cable back into
the switch is not replicated. Is there some config option I'm missing?

mysql> show slave status\G
*************************** 1. row ***************************
              Slave_IO_State: Waiting for master to send event
                 Master_Host: metropolisdb1
                 Master_User: replicate
                 Master_Port: 3306
               Connect_Retry: 60
             Master_Log_File: mysql-bin.000001
         Read_Master_Log_Pos: 107
              Relay_Log_File: gothamdb1-relay-bin.000002
               Relay_Log_Pos: 253
       Relay_Master_Log_File: mysql-bin.000001
            Slave_IO_Running: Yes
           Slave_SQL_Running: Yes
             Replicate_Do_DB: test
         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: 107
             Relay_Log_Space: 413
             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: 2
1 row in set (0.00 sec)


mysql> show slave status\G
*************************** 1. row ***************************
              Slave_IO_State: Waiting for master to send event
                 Master_Host: gothamdb1
                 Master_User: replicate
                 Master_Port: 3306
               Connect_Retry: 60
             Master_Log_File: mysql-bin.000001
         Read_Master_Log_Pos: 53875
              Relay_Log_File: metropolisdb1-relay-bin.000002
               Relay_Log_Pos: 54021
       Relay_Master_Log_File: mysql-bin.000001
            Slave_IO_Running: Yes
           Slave_SQL_Running: Yes
             Replicate_Do_DB: test
         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: 53875
             Relay_Log_Space: 54185
             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
1 row in set (0.00 sec)

Regards,

Sashan
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Thread
replication after network link failureSashan Govender21 Feb
  • Re: replication after network link failureJohan De Meersman21 Feb
    • RE: replication after network link failureSashan Govender22 Feb
      • Re: replication after network link failureJeremy Zawodny22 Feb
        • RE: replication after network link failureSashan Govender22 Feb