I've got a machine that has the following config:
Each node has two InfiniBand ports:
* The first port is on fabric 'a' with switches for 'a'
* The second port is on fabric 'b' with separate switches for 'b'
* The two fabrics are not shared ('a' and 'b' can't communicate with one
I believe that Open MPI is perfectly capable of stripeing over both fabric
'a' and 'b', and IIRC, this is the default behavior.
Does Open MPI handle the case where Open MPI puts all of its traffic on
the first IB port (ie. fabric 'a'), and leaves the second IB port (ie.
fabric 'b') free for other uses (I'll use NFS as a humorous example).
If so, is there any magic required to configure it thusly?