[Linux-cluster] multicast howto
Patrick Caulfield
pcaulfie at redhat.com
Wed Apr 26 13:17:17 UTC 2006
Steven Dake wrote:
> 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.
Good advice.
I've fixed the Wiki page, so it reflects reality a little more. I don't know
where that came from but it was confusing.
--
patrick
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