I have tried this tool, it's really a great tool in doing the master failover.
I have one question:
In the wiki, the relay_log_purge is suggested to be set to OFF. I did that and start testing the failover. After the failover is successfully done and I checked this parameter again and it's set back to ON.
It means I have to set them to OFF manually before I start the manager next time. Is it designed to be this?
August 24, 2011 6:42 PM
Yoshinori Matsunobu said...
@Anonymous
relay_log_purge is implicitly turned to ON by MySQL itself sometimes, including when executing CHANGE MASTER. MHA internally executes CHANGE MASTER so relay_log_purge is set to ON. This applies when you execute CHANGE MASTER manually, too.
I can modify MHA Manager to check relay_log_purge parameter before executing CHANGE MASTER and set that value (executing SET GLOBAL relay_log_purge=0 or 1) after executing CHANGE MASTER, but I recommend another approach: Executing relay_log_purge script included in MHA Node package regularly, and setting --disable-relay-log-purge argument. See the online manual for details.
http://code.google.com/p/mysql-master-ha/wiki/Requirements#purge_relay_logs_script
By using this, you can safely remove unneeded relay logs and set relay_log_purge=0 automatically.
August 24, 2011 7:12 PM
yoshinorim
commented
13 years ago
http://yoshinorimatsunobu.blogspot.com/2011/07/announcing-mysql-mha-mysql-master-high.html#comments
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Yoshinori Matsunobu said...