[Linux-cluster] Few queries about fence working

[jayesh.shinde at netcore.co.in]

Dear Digimer & Kaloyan Kovachev ,

Do u think this server shutdown problem ( while fencing simultaneously from both node via drbd.conf) can be completely avoid  if I use SAN disk instead of DRBD disk ?

i.e  in case of SAN disk the defined fence config under cluster.conf will take care of the n/w failuer and related fencing of node ?

What you will suggect ,  SAN or DRBD disk.
please guide me.

Regards
Jayesh Shinde

Quoting Digimer <linux at alteeve.com>:

> On 01/25/2012 08:57 AM, jayesh.shinde wrote:
>> Hi Kaloyan Kovachev ,
>>
>> I am using below config  in drbd.conf  which is mention on DRBD cookbook.
>>
>> }
>>   disk {
>>     fencing resource-and-stonith;
>>   }
>>   handlers {
>>     outdate-peer "/sbin/obliterate";
>>
>> Under  /sbin/obliterate script , "fence_node" is mention.
>>
>> *Do you know what is the default method with "**fence_node $REMOTE" *i.e
>> reboot of power-off ?
>>
>> Dear Digimer ,
>>
>> Can you please guide me here.
>>
>> Currently I am not having the test machine to test it , so all member's
>> inputs will help me a lot to understand it.
>>
>> Below is the /sbin/obliterate
>
> I updated the tutorial to address this last night;
>
> https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial#Hooking_DRBD_Into_The_Cluster.27s_Fencing
>
> and
>
> https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial#Configuring_DRBD_Global_and_Common_Options
>
> In short; this is a problem where the fence device, IPMI and DRAC here,
> get the call to shut down their host but don't act on it fast enough to
> block the call heading to the other node.
>
> The obliterate scripts (obliterate is an older version of
> obliterate-peer.sh, which I am working to replace with rhcs_fence now)
> call cman to remove the peer node from the cluster, then call the actual
> fence. For this reason, the delay set in cluster.conf won't help.
>
> The options are to add a 'sleep 10;' to the start of *one* node's
> obliterate or obliterate-peer.sh script. Alternatively, rhcs_fence uses
> the node's ID to calculate a delay automatically to help avoid these
> dual-fence scenarios.
>
> --
> Digimer
> E-Mail:              digimer at alteeve.com
> Papers and Projects: https://alteeve.com
>

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