[Wrf-users] test cases and run parameters for I/O study

[Wei-keng Liao]

Hi, Min,

Thanks for your kind suggestion.

My understanding by far is the WRF I/O patterns do not seem to change
from one historical checkpoint/restart to another. If this is true,
I do not mind a large file size and a large number of variables. In
fact the parameter settings for production runs (in sequential or parallel)
will be ideal for me, as long as I can control the run time to be
within 5-10 minutes for study purpose. My plan is to develop some
I/O techniques (hopefully to improve performance) and evaluate them
on HPC computers (with large data in TBs range).

I hope those control parameters mentioned in my previous email are
the right ones. Can I assume the output variables preset in the registry
file for the test cases are closed to the typical WRF uses? I tested
em_tropical_cyclone and it writes 148 variables in each history checkpoint.


Wei-keng

On Jun 18, 2014, at 3:30 AM, Min Zhu wrote:

> I think that you can reduce the file size by reducing the number of output variables either through the registry file or through run time text file README.io_config or you can compress your NetCDF file (Beginning with V3.5, the compression function in netCDF4 is supported).
> 
> Regards,
> 
> Min Zhu
> 
> -----Original Message-----
> From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On Behalf Of Wei-keng Liao
> Sent: 17 June 2014 23:29
> To: wrf users group
> Subject: [Wrf-users] test cases and run parameters for I/O study
> 
> Hi,
> 
> I am studying WRF's I/O pattern and wondering if I can get some recommendations on choosing a test case and its run-time parameters.
> The ideal parameter setting is that can produce a large domain size (I/O amount) and a short run time (with 3-5 output time snapshots).
> 
> I tried the test case "test/em_tropical_cyclone" and changed the following parameters in file namelist.input.
> run_days                            = 0,
> run_hours                           = 0,
> run_minutes                         = 10,
> history_interval                    = 5,
> s_we                                = 1,
> e_we                                = 401,
> s_sn                                = 1,
> e_sn                                = 401,
> s_vert                              = 1,
> e_vert                              = 121,
> 
> The above settings took about 10 minutes and produced an output file of size 3.3GB (with 3 time snapshots). I wonder if I am on the right track and will very appreciated if the experts in the WRF community can kindly provide me additional suggestions.
> 
> Wei-keng Liao
> 
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