Certainly. That third node need not run any cluster services at all other than
fencing, and yet would guarantee a quorum in the even of loss of any single
node.
A quorum disk would theoretically solve this as well, but for reasons I can't
quite articulate I suspect the three-node cluster is superior. (Besides, we
have stockpiles of cheap hardware where I'm at, so there's little reason for us
not to do it.)
________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rodrique
Heron
Sent: Friday, October 24, 2008 12:00 PM
To: linux clustering
Subject: Re: [Linux-cluster] Two nodes cluster issue without
sharedstorageissue
Jeff
I have two node cluster only because my storage array only supports two
nodes, can I add a third node without it having access to the storage? I am
using CLVM to run domU's.
Jeff Sturm wrote:
For what it's worth, considerations like these have caused us
to abandon any efforts to build a 2-node cluster.
>From this point forward all our RHCS deployments will have a
minimum of 3 nodes, even if the 3rd node is a small node that provides no
resources and only exists for arbitration purposes. (It was going to be that,
or a quorum disk for our application, but we have no experience running a
quorum disk over the long-haul in a production envrironment.)
Hope this helps someone.
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Chen,
> Mockey (NSN - CN/Cheng Du)
> Sent: Thursday, October 23, 2008 10:36 PM
> To: linux clustering
> Subject: RE: [Linux-cluster] Two nodes cluster issue without
> sharedstorageissue
>
>
>
> >-----Original Message-----
> >From: [EMAIL PROTECTED]
> >[mailto:[EMAIL PROTECTED] On Behalf Of ext Lon
> >Hohberger
> >Sent: 2008年10月24日 0:02
> >To: linux clustering
> >Subject: Re: [Linux-cluster] Two nodes cluster issue without
shared
> >storageissue
> >
> >On Thu, 2008-10-16 at 17:10 +0800, Chen, Mockey (NSN -
CN/Cheng Du)
> >wrote:
> >> Hi,
> >>
> >> I want to set up a two node cluster, I use active/standby
> >mode to run
> >> my service. I need even one node's hardware failure such as
> >power cut,
> >> another node still can handover from failure node and the
> >provide the
> >> service.
> >>
> >> In my environment, I have no shared storage, so I can not
> use quorum
> >> disk. Is there any other way to implement it? I searched
and found
> >> 'tiebreaker IP' may feed my request, but I can not found
any
> >hints on
> >> how to configure it ?
> >
> >Since you have no shared data, you may be able to run
> without fencing.
> >
> >That should be pretty straightforward, but you might need to
comment
> >out the "fenced" startup from the cman init script.
> >
> >In this case, the worst that will happen is both nodes will
end up
> >running the service at the same time in the event of a
network
> >partition.
> >
> >The other down side is that if the cluster divides into two
> partitions
> >and later merges back into one partition, I don't think
> certain things
> >will work right; you will need to detect this event and
> reboot one of
> >the nodes.
> >
> >-- Lon
>
> I know such defects in two node cluster.
> Since our service is mission critical, I want to know how to
> avoid such failure case ?
>
> Thanks.
>
>
>
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>
>
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