[Linux-cluster] Starting a cluster - Quorum Numbers

[Jonathan E Brassow]

You must achieve quorum before the cluster services are enabled.  That 
means 1/2 of your machines listed in cluster.conf +1 must come up.

After that, if you do a 'cman_tool leave remove' on the machines you 
don't need, you should be able to go down as low as you want.  (I think 
there is a way to make the cman initscript do this automatically...  I 
also think you can specify a node count or quorum number in 
cluster.conf to control when it's allowed to start the service - but 
this last one might be unlikely, given that it could lead to 
split-brain.)

Hopefully, someone with more knowledge will expand on this.

  brassow

On Jan 24, 2007, at 1:34 PM, isplist at logicore.net wrote:

> Perhaps I've missed this somewhere but here I ask :).
>
> I don't have a fixed number of nodes in my cluster. I sometimes use 4
> machines, sometimes 8, sometimes more. I could split the clusters up 
> but it
> would be simpler for me if I could only turn up the nodes I need as I 
> need
> them.
>
> The problem;
>
> When I start my cluster, it locks up at DLM waiting on other nodes to 
> come up.
> If I don't need them all, then I only fire up the ones I need but then 
> DLM
> remains locked up until I turn up yet more nodes.
>
> I believe this is related to my cluster.conf file but I've yet to find 
> enough
> information that will explain how I can get around this problem.
>
> Can someone shed some light?
>
> Mike
>
>
>
>
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