Subject: WRF-Chem Version 4.4 Performance and RSL File Size Optimization

[Varun Katoch]

Hello Everyone,

I hope this email finds you well. I am reaching out regarding some performance and file size issues we are encountering with our WRF-Chem version 4.4 simulations.

1) Performance Improvement:
   I have observed that our simulations are running significantly slower than expected, particularly when dealing with nested domains. For instance, it currently takes around 2 hours to write one hour of wrfout output. This is posing challenges as we aim to run simulations spanning over one month. We are keen on exploring any possible optimizations or best practices to enhance the performance of our WRF-Chem runs. Are there any specific configurations, compiler options, or runtime settings that we could adjust to expedite the simulation process?

#!/bin/sh
#SBATCH -p defq
#SBATCH -J wrf_chem_opt_10_D02_GFS
#SBATCH -o main_02.out
#SBATCH --mail-user
#SBATCH --mail-type=ALL
#SBATCH -N 4
#SBATCH -n 50

2) RSL File Size Optimization:
   Additionally, I have noticed that the size of our rsl.out.0000 file is unmanageably large, approximately 250 GB. We suspect that WRF-Chem might be overwriting this file at every step, leading to its substantial growth. Could you please provide guidance on how we can mitigate this issue? Are there any settings or strategies we can employ to limit the size of these diagnostic files without compromising the essential information they provide?

For your reference, I have attached the relevant namelist file.

Thank you for your time and assistance. We look forward to your prompt response.

Best regards,

[Mary Barth]

Hello Varun,

It is better to post these questions on the WRF forum where a broader audience can help you.

Perhaps before doing that you could see if you get the same issues when running only one domain, and when running chem_opt=0. That way you have a sense of whether running 2 domains is substantially affecting the performance and if whether the chemistry is substantially affecting the performance. 

Good luck,

Mary

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Mary Barth 

Senior Scientist   

phone: 303-497-8186    email: bar...@ucar.edu

NSF - National Center for Atmospheric Research

P.O. Box 3000

Boulder, CO 80307

Staff web page

SIMA Web Site

MUSICA Web Site

DC3 Web Site 

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On Thu, Feb 15, 2024 at 1:18 AM Varun Katoch <varunkato...@gmail.com> wrote:

Hello Everyone,

I hope this email finds you well. I am reaching out regarding some performance and file size issues we are encountering with our WRF-Chem version 4.4 simulations.

1) Performance Improvement:
   I have observed that our simulations are running significantly slower than expected, particularly when dealing with nested domains. For instance, it currently takes around 2 hours to write one hour of wrfout output. This is posing challenges as we aim to run simulations spanning over one month. We are keen on exploring any possible optimizations or best practices to enhance the performance of our WRF-Chem runs. Are there any specific configurations, compiler options, or runtime settings that we could adjust to expedite the simulation process?

#!/bin/sh
#SBATCH -p defq
#SBATCH -J wrf_chem_opt_10_D02_GFS
#SBATCH -o main_02.out

#SBATCH --mail-user varun....@imt-nord-europe.fr

#SBATCH --mail-type=ALL
#SBATCH -N 4
#SBATCH -n 50

2) RSL File Size Optimization:
   Additionally, I have noticed that the size of our rsl.out.0000 file is unmanageably large, approximately 250 GB. We suspect that WRF-Chem might be overwriting this file at every step, leading to its substantial growth. Could you please provide guidance on how we can mitigate this issue? Are there any settings or strategies we can employ to limit the size of these diagnostic files without compromising the essential information they provide?

For your reference, I have attached the relevant namelist file.

Thank you for your time and assistance. We look forward to your prompt response.

Best regards,

[Your Name]
[Your Position/Title]
[Your Contact Information]