This appears to be similar to the problem described in:

However, those fixes do not work for me.

I am running on an

- i5 sandy bridge under Ubuntu 10.10 8 G RAM

- Kernel 2.6.32.14 with OpenVZ tweaks

- OpenMPI V 1.4.1

I am trying to migrate existing software to a new cluster (A,B)

Symptoms:

I can run the ring demo on a single machine, either A or B with any number of processes.

But when I combine the 2 machines I am limited to 2 processes, any more and MPI hangs. It gets as far as:

Process 0 sending 10 to 1, tag 201 (3 processes in ring)

Process 0 sent to 1

and there it stays...

Any help greatly appreciated.