Flexible IO for ufs-weather-model

[saeed-moghimi-noaa]

To fallow up:
@janahaddad @uturuncoglu

[saeed-moghimi-noaa]

[janahaddad]

Another presentation from Dan Rosen about various solutions they are exploring for asynchronous IO:

Current problem to be solved:

• there are inconsistent I/O solutions (diff file formats, bad metadata handling, everything is custom)
• the solutions that exist are often redundant and very specific
• need shared solutions

Tiers of the solution:

• non-parallel, non-dedicated :
  • Worst "solution"
  • all the asynchronous HPC node tasks send all output to just 1 task that is both running a forecast and writing the output to disk.
• parallel, non-dedicated:
  • a bit better
  • each tasks does its own IO
  • each task competes to write to disk, bottleneck
• parallel, dedicated, inter-node
  • some number of tasks are dedicated to I/O (output only in his schematic)
  • still need to send data across the network to get it to disk
  • but solves problem of competing to get to disk
• parallel, dedicated, intra-node
  • I/O task is on the same node

The last 2 are what they are trying to get to, but want to abstract it from the end-user

[janahaddad]

3 potential solutions to the problem:

1. 3rd party library
   

2. Dedicated NUOPC IO Component that uses shared infrastructure
   

3. Built-in NUOPC Model: take the existing model component and split its resources internally, givign the options to the user