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-   -   RedHat CLuster fencing general question (http://www.linuxquestions.org/questions/linux-newbie-8/redhat-cluster-fencing-general-question-682990/)

Josephwpc 11-12-2008 07:32 PM

RedHat CLuster fencing general question
 
I have a general hencing question for the Redhat cluster.
My cluster setting is:
1. two-nodes cluster.
2. 3 service resources. All of them have floating IP assigned.
3. No shared resources/storage (the nodes access separate disks etc).
4. No network power switch.

Do I need to configure the fencing for this?

kenneho 11-13-2008 02:47 AM

Yes, you need to configure fencing for this. In fact, you don't get around fencing at all, as not as far as I know.

I think that you'll find the info you need here: http://sources.redhat.com/cluster/faq.html

Josephwpc 11-13-2008 05:25 PM

OK based on the reading from these FQA, I should configure the fencing for my two-nodes cluster, but what kind of fence device I should configured for my cluster???

Also, based on my reading, the Fencing is the component of cluster project that cuts off access to a resource (hard disk, etc.) from a node in your cluster if it loses contact with the rest of the nodes in the cluster. So for a two-nodes cluster if both nodes lose contact with each other both nodes will fencing itself, right? Is this will cause either both nodes give up the cluster ownership or both nodes own the cluster ownership? So, we need to have some kind of "tie-breaker" to solve this???

kenneho 11-14-2008 06:35 AM

Quote:

Originally Posted by Josephwpc (Post 3341134)
OK based on the reading from these FQA, I should configure the fencing for my two-nodes cluster, but what kind of fence device I should configured for my cluster???

Also, based on my reading, the Fencing is the component of cluster project that cuts off access to a resource (hard disk, etc.) from a node in your cluster if it loses contact with the rest of the nodes in the cluster. So for a two-nodes cluster if both nodes lose contact with each other both nodes will fencing itself, right? Is this will cause either both nodes give up the cluster ownership or both nodes own the cluster ownership? So, we need to have some kind of "tie-breaker" to solve this???

( First of all, I'm not an expert on RedHat fencing, so double check my answers if you're in doubt. Or contact support. :) )

I don't know what kind of fence device you should use. Most go for at network power switch it seems.

It the two nodes loose contact with each other they will start fencing each other. I have also seen that a node kills itself in such a scenario, and I think this has to do with some kind of timeout mechanism (don't recall its name).

The cluster manager implements a mechanism called "quorum" to ensure that the "split-brain" scenarios you described does not occur.

viral_Ahire 02-18-2009 11:30 PM

RHEL-5 Cluster Suite
 
As far as my Experience is concern in RHEL-5 Cluster ,u have to configure fencing device in ur cluster. If u r using HP server ,u can use ILO as a Fencing device.


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