[Linux-cluster] < cluster.conf problem >

Wed Apr 19 17:32:00 UTC 2006

Hi...

Thanks for the answer..

Lee

He who has a why to live can bear with almost any how.
Friedrich Nietzsche

________________________________

From: linux-cluster-bounces at redhat.com on behalf of Jonathan E Brassow
Sent: Wed 2006/04/19 06:45 PM
To: linux clustering
Subject: Re: [Linux-cluster] < cluster.conf problem >

Quorum is a number of machines greater than or equal to (n/2 +1) of the total cluster machines. 
There is no way for two groups of machines in a cluster to have "quorum". Only one group (which may be all the machines) can have this status. 

When a group of machines has quorum, they can perform cluster operations. The idea of quorum prevents "split-brain" or two separate groups of machines from thinking they are in control of the cluster - and thus potentially corrupting resources because they do not acknowledge the existence of the other group. (Think multiple writer problem.) 

You should reboot all your machines at the same time. (Or at least do cman_tool join on all the machines at close to the same time.) This allows the machines to form a quorate group and start performing cluster operations - like starting and performing fencing. 

brassow 

P.S. Manual fencing sucks for anything more than simple evaluation. My guess is that you will encounter more problems/questions because of manual fencing. 

On Apr 19, 2006, at 9:28 AM, Pool Lee, Mr <14117614 at sun.ac.za> wrote: 

	Hi... 

	I did that, thanks. 

	Now I have trouble getting fence_tool join to work. I did cman_tool join and I'm able to see the nodes under /proc/cluster/nodes... 

	But fence seems to wait for something called  "quorum".. 
	In the cluster.conf file just said fence manually... 

	What would be the problem? 

	Lee 

	He who has a why to live can bear with almost any how. 
	Friedrich Nietzsche 

	From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Jonathan E Brassow 
	Sent: 19 April 2006 04:14 PM 
	To: linux clustering 
	Subject: Re: [Linux-cluster] < cluster.conf problem > 

	Have you started the CCS daemon (ccsd)? The init script should start this on bootup. You really just need to create the cluster.conf file (by hand or by GUI) and copy it to all your nodes. Then reboot. 

	brassow 

	On Apr 18, 2006, at 3:14 PM, Pool Lee, Mr <14117614 at sun.ac.za> wrote: 

		Hi... 

		I have 5 nodes and 1 head node. I want to setup gfs so that I can bunch together the 5 nodes, each have lvm's. 

		I'm having trouble setting up cluster.conf. I follow the manuals example for gfs, not gfs2, and it says that it cant connect to css. 

		I'm running FC5 on all my machines. 

		Lee 

		He who has a why to live can bear with almost any how. 
		Friedrich Nietzsche  

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