topic Re: 3 node cluster with two network in Operating System - HP-UX

3 node cluster with two network

Anoop.Panakool — Wed, 22 Aug 2007 08:01:04 GMT

Hello,

We are planning to setup 3 node cluster. One of the server should act stanby for other two servers.My issue is that two servers have two different network and all have one common network. May be my diagram might say better. (server 2 should run app1 and app3 in the event of server 1,server3 failure .

Does this configuration supported in service guard.if yen anything special I need to take care of? Can any one help/guide me

Re: 3 node cluster with two network

Steven E. Protter — Wed, 22 Aug 2007 08:14:39 GMT

Shalom,

If you want a package/application to be available to users and be able to run on all three nodes, these and perhaps other conditions must be met:

1) The floating ip the users use must be on the network common to all three systems.
2) The users must have access, direct or via routing to the common network.
3) There must be a heartbeat mechanism between all three nodes. This may be a problem based on the fact the systems don't have a common second network. You may need to set up a quorom server on the common network, but this makes that network the single point of failure that will cause a TOC on the cluster if there is a failure. That will drop two nodes right out of the cluster.

SEP

Re: 3 node cluster with two network

Anoop.Panakool — Thu, 23 Aug 2007 00:21:01 GMT

Thank you very mych stev for you reply.

I do not need to run my all pacakages/ application on all three nodes. I want app1 should failover to server two. And app2 and app3 should be failover between server2 and server 3, in other way I dont need to run app3 on server 1 and app1 on server 3.

app2 and app3 will be having package IP in 193.188.XX.XX and app1 will in 192.168.XX.XX.

App2 an App3 users will be connecting through 193.188.XX.XX network.

Hope this clarify my question little better.

Re: 3 node cluster with two network

Matti_Kurkela — Thu, 23 Aug 2007 04:16:21 GMT

It's not an "optimal" cluster, but yes, it can be done.

The cluster is not "optimal" because it has a critical node: if server2 goes down for any reason, you cannot tolerate any more server failures without inevitably losing something.

If this is acceptable, go ahead. But I recommend you make the limitations of this setup absolutely crystal clear to yourself, your fellow admins and your bosses.

Simply adding two more LAN connections to server1 would allow you to make the servers identical, so that any application can move to any server. This would make the cluster a lot more flexible in failover situations.

MK

Re: 3 node cluster with two network

Stephen Doud — Thu, 23 Aug 2007 07:40:50 GMT

The image does not show the storage connections. It appears that server 2 and 3 can run server 1's application package, and that server 2 and 3 can swap application packages.

The image seems to validate your goal.