1. Well, I was re-added slave nodes to cluster, so It work well (now). I
will leave cluster idle on all night for repeat this error and show you
unclean state and logs

2. Thanls a lot for this advice! But I don't understand one thing - how to
switch slave from sync to async mode? Yes, I want all nodes in async. The
data loss is not important.




2013/12/11 Takehiro Matsushima <[email protected]>

> Sorry for my late reply...
>
> > 1. Why slaves stay disconnected? How I can found reason?
>
> It seems that slaves are connected properly.
> master-pgsql:1 on Node b has score 100, means it can promote when
> current master failed.
>
> > Node Attributes:
> > * Node b.mydomain.com:
> >     + master-pgsql:0                   : -INFINITY
> >     + master-pgsql:1                   : 100
> >     + pgsql-data-status               : STREAMING|SYNC
> >     + pgsql-status                     : HS:sync
> >     + pgsql-xlog-loc                   : 000000000E0000C8
>
> You can confirm any changes replicate to slaves by;
> 1. INSERT on Master
> 2. SELECT on one of slave
> 3. Same on another one
>
>
> > 2. Why one node stay as sync replication, but other is async?
>
> I've also been asked to Mr. MATSUO about this thing.
>
> 1. PostgreSQL has 4 states, Master, Sync, Potential and Async.
> 2. Sync slave node is only one, and others are Async.
> 3. One of Async slave is able to change Sync when Sync slave failed,
> it called Potential.
> 4. Changing Potential to Sync is controlled by PostgreSQL, NOT Pacemaker.
>
> He showed to me the situation following;
>
> 1. Node A is Master, Node B is Sync slave, Node C is Potential Async slave.
> 2. Node B's replication line has down, then PostgreSQL promotes Node C
> to Sync slave and responses COMMIT OK to client.
> 3. But, Pacemaker doesn't know this event yet.
> 4. After that Node A crashed, then Pacemaker tries to promote Node B,
> it known Sync slave.
> 5. Consistency is broken.
>
> So, the 3rd node is set Async intentionally, Mr. MATSUO answered.
> And also refer followings he said.
>
> https://github.com/ClusterLabs/resource-agents/commit/55494b5052f540030938733ec4729cc37ac64a8c
> https://github.com/t-matsuo/resource-agents/issues/24
>
>
> --
> Regards,
> Takehiro Matsushima
> _______________________________________________
> Linux-HA mailing list
> [email protected]
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
> See also: http://linux-ha.org/ReportingProblems
>
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