[mpich-discuss] MPI IO on lustre

[burlen]

Our simulation that is currently running on order of 1E4 processes, and 
fast approaching 1E5 processes. IO is a substantial bottleneck.

The book "Using MPI-2: Advanced Features of the Message-Passsing 
Interface" makes the case that collective IO is one of the best option 
for an HPC application. In contrast I have read more recent studies 
which show that MPI-IO performs poorly on Lustre fs which is deployed 
ubiquitously on the systems we use. Some study even advocate abandoning 
MPI-IO in place of single file direct access via posix api. Which is to 
say MPI-IO delivers no optimization at all.

I am very curious as to the current state of Lustre ADIO in mpich2 , and 
its future direction. Obviously fine tuning of both Lustre parameters 
and MPI-IO hints for the specific situation are critical. If the fine 
tuning is done reasonably well, can we expect high-preformance from MPI 
collective IO on Lustre fs currently or in the near term?

Thanks
Burlen