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Hi,<br>
<br>
Ruzsinszky Attila wrote:
<blockquote
cite="mid:AANLkTi=2D7NHrZvFLAGOe4U1X_TfiH3EvSKb58DHthtp@mail.gmail.com"
type="cite">
<blockquote type="cite">
<pre wrap="">You're not making sense, first you say MySQL Master-Master, then you
mention master mysqld on clusterB and slave mysqld on clusterA. So,
which one is it:
</pre>
</blockquote>
<pre wrap=""><!---->Yes, it is true. If I stop openais and I start mysql without openais the config
is M-M (or Multi-Master).
When pacemaker starts mysql processes I can see master and slave mysqld
text from crm_mon.
</pre>
<blockquote type="cite">
<pre wrap="">- MySQL Master-Master (or Multi-Master) which can be achieved via MySQL
Replication
- MySQL Master-Slave, which can be achieved via MySQL Replication as well
</pre>
</blockquote>
<pre wrap=""><!---->I'd like to implement the above. I don't know which one is right for me.
Because of M-M MySQL config I think the 1st one is my choice.
</pre>
</blockquote>
A MySQL Multi-Master architecture for a 2 node setup brings a lot of
configuration and administration overhead and has no conflict detection
or resolution. Integrating such a setup with Pacemaker only adds to the
overhead, as the current resource agents only handle a standalone MySQL
server. Even the LSB script doesn't handle a Multi-Master setup. You'd
have to write a custom resource agent, and it would probably fit your
setup and your setup alone, meaning it couldn't be widely used for
other setups, I know I had to make some modifications to the mysql
resource agent and those changes were specific to my setup.<br>
<br>
MySQL Cluster is a choice, it could be integrated with Pacemaker,
although I don't actually see the benefits in this case, meaning MySQL
Cluster would be the database backend, on it's own, doing it job, and
to that backend you could connect from multiple frontends, put a load
balancer (or two) before the frontends and you've got quite the setup,
and the frontends and load balancer could be controlled by Pacemaker.
But MySQL Cluster has it's downsides as well, it needs a minimum of 4
nodes (it could probably work with less but that's the general
recommendation), 2 data node, one SQL node and one management node. The
SQL and management role could be collocated on one physical node + 2
data nodes = 3 nodes.<br>
<br>
Anyways, this is just to get a feel for what's involved in the process,
and how Pacemaker would fit the picture, at least from my point of view.<br>
<br>
I would recommend all questions related to MySQL Cluster, Replication,
Multi-Master be directed to the appropriate mailing lists though, and
if you want to write a resource agent for a Multi-Master setup, by all
means, do share :)<br>
<br>
Hope this helps.<br>
<br>
Regards,<br>
Dan<br>
<blockquote
cite="mid:AANLkTi=2D7NHrZvFLAGOe4U1X_TfiH3EvSKb58DHthtp@mail.gmail.com"
type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<pre wrap="">- MySQL Master with a DRBD backend (even MySQL docs recommend this type
of setup for some use cases) in which the MySQL instance runs only where
DRBD is primary
</pre>
</blockquote>
<pre wrap=""><!---->I think I know this setup and don't want it now.
</pre>
<blockquote type="cite">
<pre wrap="">- MySQL Cluster (nothing to do with Pacemaker, although they can be put
together in a setup)
</pre>
</blockquote>
<pre wrap=""><!---->This would be the next test if I have enough time.
TIA,
Ruzsi
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dan FRINCU
Systems Engineer
CCNA, RHCE
Streamwide Romania
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