At 08:39 AM 5/28/2008, Hal Rosenstock wrote: >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.
Okay ... but IMO the only thing we need is a LID. Or at least, in my experience all I've needed is a LID. In a previous effort, we simply stole the low octet of an IP address, so we'd "ifconfig ib0 1.2.3.X" and it would jam lid=X into the interface. Worked great. If necessary, we would set a manual arp entry (using iproute) to avoid having to broadcast. > >> 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. Okay, all kernel modules can be assumed to be in place. How do we tell it to manage the LID, with a shell command? > >> 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 ? I think so, for two reasons. One, principle of least surprise - the user will expect to be able to ping, telnet etc if it has connectivity. Two, for NFS/RDMA we require TCP and UDP connections in order to perform the mount and do locking and recovery. We could do those over a parallel ethernet connection, but that's kind of not the point. > >> 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). Which, IMO, we need to boil down to simplest-possible, for at least some workable configuration. Thanks for the ideas! Tom. > >-- 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 >> [email protected] >> http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general >> >> To unsubscribe, please visit >http://openib.org/mailman/listinfo/openib-general _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
