Details
Minor Description
Currently it is required that IB networks have IPoIB configured in order to establish an initial connection to the IB peer via its IP address so that it can fetch the IB GUID. This also simplifies configuration somewhat because IP dotted-quad addresses are easier to manage than IB GUIDs. It is also possible to use DNS to perform hostname->IP lookups (e.g. to the MGS), but the current Lustre configuration logs require IP addresses to be stored because the kernel does not (or at least did not) have the ability to lookup hostnames directly (though that may have changed in newer kernels).
After that initial IP connection, o2iblnd does not use IP for any traffic.
It would be desirable to eliminate the requirement for IPoIB in networks where this is not needed, without administrators having to manage IB GUIDs directly (which are long, complex, do not necessarily follow a consistent pattern).