[Linux-cluster] multicast howto

[Steven Dake]

On Tue, 2006-04-25 at 12:38 -0600, Wolfgang Pauli wrote:
> Hi,
> 
> I am trying to setup gfs on a cluster that spans over two subnets. dream is a 
> node with to interefaces, one on each subnet. I thought the below setup 
> should work (taken from http://gfs.wikidev.net/Installation ). But it does 
> not. Can anybody tell me what is wrong with that?
> 
> cheers,
> 
> wolfgang
> 
> <?xml version="1.0" ?>
> <cluster config_version="2" name="alpha_cluster">
> 	<fence_daemon post_fail_delay="0" post_join_delay="3"/>
> 	<clusternodes>
> 		<clusternode name="dream" votes="1">
> 			<altname name"dream-e1">
> 			<multicast addr="224.0.0.1" interface="eth0"/>
> 			<multicast addr="224.0.0.9" interface="eth1"/>
> 			<fence>
> 				<method name="1">
> 					<device name="human" nodename="dream"/>
> 				</method>
> 			</fence>
> 		</clusternode>
> 		<clusternode name="neo" votes="1">
> 			<multicast addr="224.0.0.1" interface="eth0"/>
> 			<fence>
> 				<method name="1">
> 					<device name="human" nodename="neo"/>
> 				</method>
> 			</fence>
> 		</clusternode>
> 		<clusternode name="node1" votes="1">
> 			<multicast addr="224.0.0.9" interface="eth0"/>
> 			<fence>
> 				<method name="1">
> 					<device name="human" nodename="node1"/>
> 				</method>
> 			</fence>
> 		</clusternode>
> 	</clusternodes>
> 	<cman expected_votes="1" two_node="1">
> 		<multicast addr="224.0.0.1"/>
> 		<multicast addr="224.0.0.9"/>
> 	</cman>
> 	<fencedevices>
> 		<fencedevice agent="fence_manual" name="human"/>
> 	</fencedevices>
> 	<rm>
> 		<failoverdomains/>
> 		<resources/>
> 	</rm>
> </cluster>
> 

Wolfgang
Do not use the multicast address 224.0.0.1.  It is reserved for some
various ipv4 operations.

Try using 225.0.0.9.  If you have a switch between the two subnets, I
would expect RHCS to work.  If you have a router, I'd expect it not to
work as the TTL must be set for multicast packets to hop across routers.
For IPV6 the hop count must be set.  It appears you are using ipv4.

If you have a switch and it doesn't work, try turning off IGMP filtering
in the switch +if it is a smart switch.  If it is a dumb switch it
should just work with some additional latencies.

Regards
-steve


> --
> Linux-cluster mailing list
> Linux-cluster at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-cluster