[ofa-general] Infiniband back-to-back without OpenSM?

[Hal Rosenstock]

Tom,

On Wed, 2008-05-28 at 08:06 -0400, Talpey, Thomas wrote:
> Is it possible to manually configure two Infiniband ports to operate
> with one another in back-to-back mode, without running OpenSM
> on one of them?

This is possible but something would need to do at least some subset of
what the SM does depending on the precise requirements and the limits
placed on the environment supported without a "full blown" SM.

> We have done this on other IB implementations by manually assigning
> LIDs, but I discover that the "lid" entry below /sys/class/infiniband/<device>
> is not writable, at least for mthca.

This can be done via MADs so user_mad kernel module would be needed to
do this.

> Also, I expect that the ipoib driver will
> be unable to join the broadcast group, so will be unwilling to come up fully.

Is IPoIB a requirement ?

> With ethernet, and maybe iWARP, just a simple ifconfig can do this. So why
> not IB?

The simple answer is that it is the nature of IB management (being
different than ethernet).

-- Hal

> If you're wondering, my goal is give NFS/RDMA users a way to avoid having
> to install the many userspace modules needed to do this, including libibverbs,
> opensm, etc. There's a lot to get wrong, and things go missing. Seeking an
> "easy" way to get started with just the kernel and some shell commands.
> 
> Tom.
> 
> _______________________________________________
> general mailing list
> general at lists.openfabrics.org
> http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general
> 
> To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general