[Linux-cluster] GFS2 Test setup

Scooter Morris scooter at cgl.ucsf.edu
Tue Oct 21 13:55:06 UTC 2008


Christine,
    Thanks for the information.  I checked my routing, and other than 
the zero conf route on the
same interface as my private network, everything seems clean.  I moved 
the zero conf route to
the public network, so we'll see if that fixes anything.  Also, the 
multicast route doesn't get involved,
does it?  The default route is on our public network (obviously) and the 
nodes should be talking to
each other over the private network (according to cman_tool status), but 
I don't know what interface
the multicasts will be sent out from.  I wouldn't think that would 
impact dlm, only the heartbeat, right?

Thanks again!

-- scooter

Christine Caulfield wrote:
> Scooter Morris wrote:
>   
>> We are in the process of building a cluster, which will hope to put into
>> production when RHEL 5.3 is released.  Our plan is to use GFS2, which
>> we've been experimenting with for some time, but we're having some
>> problems.  The cluster has 3 nodes, two HP DL580's and one HP DL585 --
>> we're using ILO for fencing.  We want to share a couple of filesystems
>> using GFS2 which are connected to our SAN (an EVA 5000).  I've set
>> everything up and it all works as expected, although on occasion, GFS2
>> just seems to hang.  This happens 1-4 times/week.  What I note in the
>> logs are a series of dlm messages.  On node 1 (for example) I see:
>>
>> dlm: connecting to 3
>> dlm: connecting to 2
>> dlm: connecting to 2
>> dlm: connecting to 2
>> dlm: connecting to 3
>> dlm: connecting to 2
>> dlm: connecting to 2
>> dlm: connecting to 2
>> dlm: connecting to 3
>> dlm: connecting to 3
>> dlm: connecting to 3
>> dlm: connecting to 3
>>
>> On node 2, I see:
>>
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>>
>> and on node 3, I see:
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>> dlm: got connection from 1
>> Extra connection from node 1 attempted
>>
>>     
>
> Those messages are usually caused by routing problems. The DLM binds to
> the address it is given by cman (see the output of cman_tool status for
> that) and receiving nodes check incoming packets against that address to
> make sure that only valid cluster nodes try to make connections.
>
> What is happening here (I think - it sounds like a problem I've seen
> before) is that the packets are being routed though another interface
> than the one cman is using and the remote node sees them as coming from
> a different address. This can happen if you have two ethernet interfaces
> connected to the same physical segment for example.
>
> There was a also a bug that could cause this if the routing was not
> quite so broken but a little odd, though I don't have the bugzilla
> number to hand, sorry.
>   

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