[Lustre-discuss] Understanging LNET routing

[David Dillow]

On Mon, 2013-08-19 at 16:50 +0400, Vsevolod Nikonorov wrote:
> Is it possible to route Lustre traffic between two TCP networks?

Yes, and you have multiple ways to achieve that goal. If you are using
TCP, then it routes just like any other IP traffic -- you may not even
need Lustre routers.

If you are trying to change LNET types -- say from RDMA over IB to TCP
-- you would run an LNET router to handle the protocol translation.

There are other reasons to run LNET routers, such as maintaining
separation between networks or fabrics, but in many cases those are more
administrative or performance based than absolute technical
requirements.

>  Manual states that
> 
> "the routers would enable LNet forwarding since their NIDs are
> specified in the 'routes' parameters as being routers."
> 
> How can I query the router if it consideres itself a router?

Look in /proc/sys/lnet/routes; if you see "Routing enabled" then the
router knows it is a router.

Hope this helps,
-- 
Dave Dillow
National Center for Computational Science
Oak Ridge National Laboratory
(865) 241-6602 office