[Users] Avoiding writing one checkpoint file per MPI process

[Erik Schnetter]

Lorenzo

The thorn `Carpet/CarpetSimulationIO` can write N output files on M
processes, and uses an efficient mechanism to map in between. That is,
it uses the high-speed interconnect instead of disk I/O to exchange
data.

This thorn is, to my knowledge, not used in production, so you'd want
to test it before you use it. It needs the `SimulationIO` external
library.

-erik

On Thu, Oct 6, 2022 at 12:28 PM Lorenzo Ennoggi
<lorenzo.ennoggi at gmail.com> wrote:
>
> Hello,
> In order to avoid stressing the filesystem on the cluster I'm running on, I was suggested to avoid writing one output/checkpoint file per MPI process and instead collecting data from multiple processes before outputting/checkpointing happens. I found the combination of parameters
>
> IO::out_mode       = "np"
> IO::out_proc_every = 8
>
> does the job for output files, but I still have one checkpoint file per process. Is there a similar parameter, or combination of parameters, which can be used for checkpoint files?
>
> Thank you very much,
> Lorenzo Ennoggi
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-- 
Erik Schnetter <schnetter at gmail.com>
http://www.perimeterinstitute.ca/personal/eschnetter/