On 25/10/14 03:32 PM, Andrew wrote:
Hi all.
I use Percona as RA on cluster (nothing mission-critical, currently -
just zabbix data); today after restarting MySQL resource (crm resource
restart p_mysql) I've got a split brain state - MySQL for some reason
started first at ex-slave node, ex-master starts later (possibly I've
set too small timeout to shutdown - only 120s, but I'm not sure).
After restart resource on both nodes it seems like mysql replication was
ok - but then after ~50min it fails in split brain again for unknown
reason (no resource restart was noticed).
In 'show replication status' there is an error in table caused by unique
index dup.
So I have a questions:
1) Which thing causes split brain, and how to avoid it in future?
Cause:
Logs?
Prevent:
Fencing (aka stonith). This is why fencing is required.
2) How to resolve split brain state? Is it enough just to wait for
failure, then - restart mysql by hand and clean row with dup index in
slave db, and then run resource again? Or there is some automation for
such cases?
How are you sharing data? Can you give us a better understanding of your
setup?
--
Digimer
Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without
access to education?
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