[Linux-cluster] Halt nodes in cluster with cable disconnect

[Miguel Angel Guerrero]

Digimer
the echo c > /proc/sysrq-trigger; command works fine the node with
this command reboot thank to the fence-peer :) in a scenary without
"fencing race", how the cluster take a decisition about what node
reboot in the cable disconnection test?
One question you think drbd works better in a pacemaker or cman environment?

Emmanuel
Your english is good, i preffer talk in spanish :P sorry for my bad
english ever i learn so much thanks to this thread

You never say me nothing about my delay fence line
<fence_daemon clean_start="0" post_fail_delay="10" post_join_delay="30"/>

Digimer And Emmanuel Thanks a lot for your help and patience

On Fri, Jan 27, 2012 at 3:31 PM, Digimer <linux at alteeve.com> wrote:
> On 01/27/2012 03:20 PM, yvette hirth wrote:
>> Digimer wrote:
>>
>>> You can crash the machine with this;
>>>
>>> echo c > /proc/sysrq-trigger
>>
>> will
>>
>> ifconfig ethx down  (where "x" = heartbeat ethernet interface numbah)
>>
>> do the same thing?
>>
>> yvette
>
> Nope. The scenario is caused by both nodes being alive, but losing the
> ability to talk to one another on the storage channel. Whether it is
> because a given cable is unplugged or a bad firewall rule, the result is
> the same; Both nodes see a failure at the same time and call their fence
> handlers at the same time. The one with the sleep will delay, and thus,
> always lose (and be the fence victim).
>
> The idea behind sending "c" to sysre-trigger is that it hangs the kernel
> entirely. The hung node will no trigger it's fence, or do anything else
> for that matter. Meanwhile, the node with the sleep will detect the
> fault, call the agent, sleep for a few seconds, then proceed to fence
> the hung node. This more accurately simulates an actual fault in the
> primary node and confirms that the sleep'ed node will in fact fence
> successfully.
>
> --
> Digimer
> E-Mail:              digimer at alteeve.com
> Papers and Projects: https://alteeve.com
>
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> Linux-cluster at redhat.com
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-- 
Atte:
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Miguel Angel Guerrero
Usuario GNU/Linux Registrado #353531
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