[Linux-cluster] 4U5 CSS/CMAN/fence quorum confusion

[Patrick Caulfield]

Robert Clark wrote:
> On Mon, 2007-06-11 at 11:05 +0100, Patrick Caulfield wrote:
>> Robert Clark wrote:
> 
>>>   Well, I was missing the dlm package. The system was still booting
>>> occasionally without it. Now I've installed that, the device file is
>>> being created in /dev/misc/dlm-control instead, but ccsd still spends
>>>> 10 seconds waiting for it to appear and fenced often fails to start as
>>> a result.
>>>
>>>   Is the delay here likely to simply be udev being slow?
>> It sounds like udev isn't creating it at all. What happens is that libdlm waits
>> 10 seconds for udev to create the device file, and if it doesn't appear after
>> that time it will do the job itself.
>>
>> Not being a udev expert I'm not really sure why that might be.
> 
>   As an experiment, I've tried just loading the dlm module on a node
> with no cluster services running and confirmed that dlm-control is being
> created by udev.
> 
>   I must admit - I'm pretty confused now about the role of libdlm. Since
> it turns out that I've been running a 4U4 cluster without the dlm
> package installed (and so no libdlm) and, until this morning, my 4U5
> cluster in the same state, I'm wondering: What uses libdlm?
> 


I don't think anything is, that might be the problem. But magma (which ccsd uses
to talk to the cluster manager) checks for the existence of dlm-controld anyway!
just in case you need to create any locks using magma I suppose.


-- 
Patrick

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