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Re: [Linux-cluster] Starter Cluster / GFS



On 10-11-11 09:22 PM, Jankowski, Chris wrote:
> Digimer,
> 
>>>>> I can't speak to heartbeat, but under RHCS you can have multiple fence methods and devices, and they will used in the order that they are found in the configuration file.
> 
> Separate hearbeat networks (not a single network with a bonded interface) is what my customers require.  I believe this is not available in standard Linux Cluster, as distributed by RedHat.  This is completely independent from what fencing device or method is used.

It is possible. ie:

<?xml version="1.0"?>
<cluster name="an-cluster" config_version="1">
    <cman two_node="1" expected_votes="1"/>
    <totem secauth="off" rrp_mode="active"/>
    <clusternodes>
        <clusternode name="an-node01.alteeve.com" nodeid="1">
            <fence>
                <method name="ipmi">
                    <device name="fence_an01" action="reboot" />
                </method>
                <method name="node_assassin">
                    <device name="batou" port="01" action="reboot"/>
                </method>
            </fence>
        </clusternode>
        <clusternode name="an-node02.alteeve.com" nodeid="2">
            <fence>
                <method name="ipmi">
                    <device name="fence_an02" action="reboot" />
                </method>
                <method name="node_assassin">
                    <device name="batou" port="02" action="reboot"/>
                </method>
            </fence>
        </clusternode>
    </clusternodes>
    <fencedevices>
        <fencedevice name="fence_an01" agent="fence_ipmilan"
ipaddr="192.168.3.61" login="admin" passwd="secret" />
        <fencedevice name="fence_an02" agent="fence_ipmilan"
ipaddr="192.168.3.62" login="admin" passwd="secret" />
        <fencedevice name="batou" agent="fence_na"
ipaddr="batou.alteeve.com" login="username" passwd="secret" quiet="1"/>
    </fencedevices>
</cluster>

In the above case, should 'an-node02' need to be fenced, the first
method 'ipmi' would be used. Should it fail, the next method
'node_assassin' would be tried.

>>>>> With the power-based devices I've used (again, just IPMI and NA), the poweroff call is more or less instant. I've not seen, personally, a lag exceeding a second with these devices. I would consider a fence device that does not disable a node in <1 second to be flawed.
> 
> 1.
> In the world where I work separate power-based devices are not an option. Blade servers do not even have power supplies. They use common power from the blade enclosure.  The only access to the power state is through service processor.

Out of curiosity, do the blades have header pins for the power and reset
switches? I don't see why they would, but I've not played with
traditional blades before.

> 2.
> We are not talking about long delays here. The whole cycle of taking the power off a blade including login to the service processor is less than 1 ms. Delay or lack thereof is not a problem.  The transactional nature of the processing is the issue.
> 
> Regards,
> 
> Chris Jankowski

Let me talk to the Red Hat folks and see what they think about
configurable per-node user-defined fence delays.

-- 
Digimer
E-Mail: digimer alteeve com
AN!Whitepapers: http://alteeve.com
Node Assassin:  http://nodeassassin.org


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