[Linux-cluster] fencing device

[John Ruemker]

Jakub Suchy wrote:
> Hi,
>
>   
>> |fencing can be a SPOF, you need two fencing devices).
>>
>> ILO is used on many sites successfully.
>>     
>
> It is. Just just have to be careful when using it.
>
>   
>> |- It's not a shared device. It MUST be on the same network path as
>> |  heartbeat.
>> Not true...  I have my ILO on my public network and my heartbeat on a private network switch.  No problems with fencing in this configuration.
>>     
>
> Talking about two node clusters: Try disconnecting your private network.
> Each node tries to fence each other, iLO is not shared and is on public
> network, therefore it may succeed. If it accidentally happens in the
> same time (and it can), all nodes will fence each other and you end up
> with powered off servers. This is what you don't want to happen...
>   

QDisk can solve this problem.

     http://sourceware.org/cluster/wiki/FAQ/CMAN#two_node_correct

John