[mpich-discuss] mpi-io mkdir

[John Bent]

Hello,

Just curious why there aren't MPI_Directory_* commands in MPI-IO.

The reason we are asking now is that PLFS will be available on LANL's
new Cielo supercomputer.  PLFS is available as both a POSIX filesystem
using FUSE and as an ADIO layer and as an API.  We have user codes that
currently query and create sub-directories for their output files.  On
most of our machines, this works just fine as they do the directory
manipulation through the POSIX filesystem and the parallel IO through
the MPIIO interface.

Unfortunately, on LANL's new Cielo supercomputer, FUSE is available only
on the login nodes and NOT on the compute nodes.  This means the above
workload fails on the directory operations since the virtual path to
PLFS files is NOT available through a mounted filesystem.  We currently
are asking the codes to use the plfs_* directory functions as a
workaround but obviously they'd prefer a pure MPI-IO solution.

Now all this is very specific to PLFS and our limited compute
environment on Cielo but perhaps this is a more general concern?
Probably it's been discussed before but I couldn't find anything in the
list archives.
-- 
Thanks,

John