[Ocfs2-users] 2 node OCFS2 clusters

[Luis Freitas]

Srinivas,

  If this is true then I would sugest OCFS2 is not taking the best decision in this scenario.

  The node that still has network connectivity should survive instead of the lowest node number. Oracle CRS has heuristics to detect if the network is down and in this scenario the node that lost network conectivy is evicted. That is why it is required to use a switch between the two nodes, instead of a cross cable. 

   OCFS2 should do the same.

Best Regards,
Luis Freitas

--- On Mon, 11/16/09, Srinivas Eeda <srinivas.eeda at oracle.com> wrote:

> From: Srinivas Eeda <srinivas.eeda at oracle.com>
> Subject: Re: [Ocfs2-users] 2 node OCFS2 clusters
> To: "Thompson, Mark" <Mark.Thompson at uk.experian.com>
> Cc: ocfs2-users at oss.oracle.com
> Date: Monday, November 16, 2009, 2:05 PM
> 
> 
> 
>   
> 
>  
> Thompson, Mark wrote:
> 
>   
>   
> 
>   2 node OCFS2 clusters
>   
> 
> 
> 
>   
>   Hi
> Srini, 
>   
>   
>   Thanks
> for the response. 
>   
>   
>   So
> are the following statements correct: 
>   
>   
>   If
> I stop the networking on node 1, node 0 will continue to
> allow OCFS2 filesystems to work and not reboot itself.
>  
>   
>   
>   If
> I stop the networking on node 0, node 1 (now being the
> lowest
> node?) will continue to allow OCFS2 filesystems to work and
> not reboot
> itself.
>   
> 
> In both the cases node 0 will survive, because that's
> the node that has
> lowest node number (defined in cluster.conf). This applies
> to the
> scenario where interconnect went down but nodes are healthy
> and are
> heartbeating to the disk.
> 
> 
>   
>   
>    
>   
>   
>   I
> guess I just need to know if it’s possible to have a
> 2
> node OCFS2 cluster that will cope with either one of the
> nodes dying,
> and have
> the remaining node still provide service.
>   
> 
> If node 0 itself panics, reboots then node 1 will survive.
> 
> 
>   
>   
> 
>   
>   
>   Regards, 
>   
>   
>   Mark
>    
>   
>   
>   
>   
>   From:
> Srinivas Eeda [mailto:srinivas.eeda at oracle.com]
> 
> 
>   Sent: 16 November 2009 14:57
> 
>   To: Thompson, Mark
> 
>   Cc: ocfs2-users at oss.oracle.com
> 
>   Subject: Re: [Ocfs2-users] 2 node OCFS2
> clusters 
>   
>   
>      
>   In a cluster with more than 2 nodes,
> if a
> network on one
> node goes down, that node will evict itself but other nodes
> will
> survive. But
> in a two node cluster, the node with lowest node number
> will survive no
> mater
> on which node network went down.
> 
>   
> 
> thanks,
> 
> --Srini
> 
>   
> 
> Thompson, Mark wrote:  
>   Hi, 
>   This is my
> first post here
> so please be
> gentle
> with me. 
>   My question is,
> can you
> have a 2 node OCFS2 cluster, disconnect one node from the
> network, and
> have the
> remaining node continue to function normally? Currently we
> have a 2
> node
> cluster and if we stop the NIC that has the OCFS2 o2cb net
> connection
> running
> on it, the other
> node
> will reboot itself. I
> have researched having a 2 node OCFS2 cluster but so far I
> have been
> unable to
> find a clear solution. I have looked at the FAQ regarding
> quorum,
>   and my OCFS2 init
> scripts are
> enabled etc. 
>   Is this
> possible, or should
> we look at alternative solutions? 
>   Regards, 
>   Mark 
>   This
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