Re: [PATCH 1/3] rdma_cm: Add support for a new RDMA_PS_LUSTRE Lustre port space

[sebastien dugue <sebastien.dugue-6ktuUTfB/bM@public.gmane.org>]

  Hi Or,

On Thu, 14 Jan 2010 16:09:43 +0200
Or Gerlitz <ogerlitz-hKgKHo2Ms0FWk0Htik3J/w@public.gmane.org> wrote:

> sebastien dugue wrote:
> > That can be done with port numbers, except that we cannot separate
> > traffic to Lustre MDS and traffic to Lustre OSS 
> 
> Looking on these patches and going with you for a minute, I don't see how this patch set serves you to assign a different QoS level (e.g SL) to MDS vs OSS related traffic. Can you elaborate on that a bit?

  If you can specify a target-port-guid to the Lustre service ID in OpenSM's
qos-policy.conf then you're all set.

  For example:

    qos-­ulps 
        default                 	      : 0 # default SL
        lustre, target-­port­guid 0x1234,0x1235 : 1 # lustre traffic to MDSs
        lustre                  	      : 2 # default lustre traffic (to OSSs)
    end­-qos-­ulps


> 
> Sean Hefty wrote:
> > Can't this be done using port numbers in the existing port space?
> 
> Indeed, Sebastien what prevents you from using the TCP port space, with one port used for MDS traffic and another port for OSS traffic? how does Lustre get ports to listen on, are they well known or you call bind with port zero and use the port allocated by the rdma-cm?

  I'm not a Lustre expert (far from it), but after talking with our Lustre guys,
it seems that all Lustre servers, OSS or MDS, use the same TCP port. So there's
no possible way to separate traffic based on TCP port only.

  Thanks,

  Sébastien.


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