[Mpi-comments] MPI_Create_directory

[Axel Huebl]

Dear MPI-Forum,


should we extend the MPI-I/O interfaces for directory operations? 
Especially a "mkdir -p" equivalent could be useful.

In many scientific apps that create output at scale, an output structure 
needs to be created on demand.

One can of course decide to do so with e.g. Linux `mkdir` but this can 
be tricky:

If all ranks do it, one will race the others and it's unnecessary 
expensive in terms of operations.

If a "root" rank does it, there is no guarantee that e.g. a MPI_Barrier 
which syncs the "MPI-World" will also cause the "filesystem-world" to be 
up-to-date. For example a mkdir on a slow NFS local node has bot yet 
propagated to the other compute nodes.

Comments, feedback and overlooked already existing solutions welcome!


Best regards,
Axel Huebl
-- 

Axel Huebl
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Institute of Radiation Physics
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