[Linux-cluster] Diskless Quorum Disk

[Chris Harms]

My nodes were set to "quorum=1 two_node=1" and fenced by DRAC cards 
using telnet over their NICs.  The same NICs used in my bonded config on 
the OS so I assumed it was on the same network path.  Perhaps I assume 
incorrectly.

Desired effect would be survivor claims service(s) running on 
unreachable node and attempts to fence unreachable node or bring it back 
online without fencing should it establish contact.  Actual result was 
survivor spun its wheels trying to fence unreachable node and did not 
assume services.  Restoring network connectivity induced the previously 
unreachable node to reboot and the surviving node experienced some kind 
of weird power off and then powered back on (???).

Ergo I figured I must need quorum disk so I can use something like a 
ping node.  My present plan is to use a loop device for the quorum disk 
device and then setup ping heuristics.  Will this even work, i.e. do the 
nodes both need to see the same qdisk or can I fool the service with a 
loop device?  I am not deploying GFS or GNDB and I have no SAN.  My only 
option would be to add another DRBD partition for this purpose which may 
or may not work.

What is the proper setup option, two_node=1 or qdisk?

Chris

Lon Hohberger wrote:
> On Wed, Jun 20, 2007 at 11:55:52AM -0500, Chris Harms wrote:
>   
>> I'm interested in using qdisk heuristics to circumvent a fencing duel in 
>> my two node cluster, however I have no shared storage so I'm mostly 
>> interested in network tests.  The FAQ indicates "You don't have to use a 
>> disk or partition to get this functionality." however Conga complains 
>> about not setting a device or label, and errors when I enter a dummy 
>> label.
>>     
>
> The FAQ is incorrect probably because of context; I'll clarify it.  You
> don't need to use *qdiskd* to prevent a 'fence duel' in the case that the
> cluster is configured in the following way:
>
> http://sources.redhat.com/cluster/faq.html#two_node_correct
>
> ... however, support for "diskless mode" is not implemented.  File a
> bugzilla / feature request so we can track it?
>
>   
>> To what should I set the device / label if I just want to ping the 
>> gateway for example?
>>     
>
> You can't right now; it uses the quorum partition to converge on things
> and do voting.
>
>