Hi Tony,
Quote Originally Posted by tonychao View Post
Hi Jens,

MySQL Replication could be set to master/master. here is an example http://www.lefred.be/node/45.
that's definitely interesting to read, but I must admit, to me it sounds & looks like providing a rather instable solution to a problem asking for MySQL Cluster. Setting that up is more work, but targets a multi-master scenario by design (i.e. synchronous updates).

Quote Originally Posted by tonychao View Post
Thanks with your explanation. Now I can decide to use SAN LUNs with OCFS2 for file data and MySQL Replication for MySQL.

I would like to ask 2 questions more:

  1. Before I stop the Tomcat or MySQL manually in the primary node (or set it to maintenance mode), I would like to confirm that there is no connection for primary node any more. Is it possible to keep serving the current connections until they are finished, but the new connections will be served in the secondary node? It seems that the IPaddr2 does not have such feature.
When I look at it from the technical point of view - how should IPaddr2 be able to do so? The clients are addressing the cluster IP address, which will always be active on a single node only... else the clients/routers wouldn't know where to send the packets to.

Quote Originally Posted by tonychao View Post

  1. Could I disable fencing in this architecture?
You can disable fencing in every architecture but why would you want to do so? Fencing is a way to make sure no resource is active on a failing node, so it can be safely restarted on one of the remaining nodes. You'll only need to provide this feature when you're running active/passive resources. If, on the other hand, you're running only active/active resources, there's no need for Pacemaker, as you can simply start the services on all nodes and use local monitoring to keep them active. So IMO, you either use Pacemaker (to run a/p resources) and you should make use of fencing - or you run no Pacemaker at all (when having only a/a resources) and fencing (in the Pacemaker sense) won't be part of the picture, either.