[Wrf-users] Memory & MPI usage

[Dan Dansereau]

To All
Two questions - if I may
Question 1
Would any one out there have any experience in the following:
1) forcing the wrf IO on a particular processing node?
2) Or forcing the IO on the head node while using the mpi ?

I am using the PGI/mpi version and changing the nio_tasks_per_group
parameter to 2 for a very large domain run.

The problem that I am having - that if the IO is done on a processing
node, the total run will take longer - or will run out of memory on the
node that is doing the IO.
By changing the machines file - I can sometimes get the right sequence
to latch it to a particular node, and even sometimes to the head node -
but most of the time - it seems that the MPI grabs the node in a random
fashion.

Question 2
Are there any advantages or disadvantages to running a 2 level nested
domain run - verses 1 larger domain at a finer resolution on a 24 hour
long simulation? - In this case a 24Km with a large 12Km nest, verses a
12Km over the same geographic area as the 24Km nested run.

Thanks in advance
Dan A. Dansereau