[ClusterLabs] MySQL cluster with auto failover

[Damiano Giuliani]

Thanks for helping me.

I'm going to know more about Galera.
What I don't like is seems I need many nodes, at least 3 for the cluster
and then at least 2 other nodes for proxy.
Asking for 5 VM is quite consuming.

As you told drbd can work only in 2 node cluster and disk replication is
not dbms replication.
Probably I'm going to try drbd on very small and low usage db.

Thanks for sharing the doc.

More I know about MySQL  more postgresql seems have better replication at
least for me.


On Wed, Sep 6, 2023, 12:40 PM Antony Stone <Antony.Stone at ha.open.source.it>
wrote:

> On Wednesday 06 September 2023 at 11:23:54, Damiano Giuliani wrote:
>
> > Thanks for helping.
> >
> > Because I still don't know which version will be provided, probably MySQL
> > enterprise or community.
>
> I believe both support Galera replication.
>
> > I was wondering about pacemaker because I know quite well how it works
> and
> > I need a vip/automatic failover
>
> I regard a VIP as being entirely independent of replicating database
> content.
>
> > Galera seems a different approach that I have to study and test
> estensively
> > before  place in production, instead pacemaker is a well know solution to
> > me.
>
> Yes, but if you are trying to replicate database content, how does
> pacemaker
> help with this?  Pacemaker can quite happily provide you with a floating
> virtual IP address which is guarenteed to be on one of your database
> servers,
> but it doesn't (as far as I know) have any mechanism for replicating the
> database content between those servers.
>
> > Is drbd approach obsolete or solid?
>
> I would say that DRBD is a solid solution provided you only have two nodes
> and
> they have very good connectivity between them.
>
> However, replicating the data at disk level is a very different matter
> from
> having a DBMS such as MySQL understanding what is on the disk (and for
> that
> matter, what it has cached in RAM).
>
> > About the degraded status I read on web there is a specific
> configuration?
>
> I cannot comment on that; maybe someone else can.
>
> > There is also a good Galera documentation to study?
>
> I used
> https://mariadb.com/kb/en/getting-started-with-mariadb-galera-cluster
>
>
> Antony.
>
> --
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