[MITgcm-support] mnc questions

[Ed Hill]

On Thu, 2005-12-15 at 13:08 -0600, Michael Schaferkotter wrote:
> just starting to experiment with mnc output.
> i notice that the output gets dumped to an .nc file for all variables and all times.
> for large domains and/or long simulations, the files could easily get to be >> large.
> i don/t see an option for dumping the output as one variable per timestep as in the *.data, *.meta dump pair.
> 
> in my domain of interest each output variable *.data file is about 220MB. for an hourly dump of a daily run, that/s at least
> 8GB. in the past we/ve had troubles with .nc files > 2GB (this may or may not still be the case).
> 
> is there a way to enable dumping into .nc format with one variable per timestep?

Hi Michael,

Yes !!!  :-)

There is an option named "mnc_max_fsize" within the data.mnc namelist
file that allows you to specify the maximum file size.  The default is
currently just a little smaller than 2GB since some other programs (eg.
the Apache web server) have serious problems with >2GB files.

And its currently documented in our "beta" documentation on-line at:

  http://mitgcm.org/r2_web_testing/latest/
  http://mitgcm.org/r2_web_testing/latest/online_documents/node254.html

which will (soon, we hope!) get cleaned up enough to become our
"standard" documentation.

And if you have any problems with MNC, please describe them here and
I'll try to fix them ASAP.

Ed

-- 
Edward H. Hill III, PhD
office:  MIT Dept. of EAPS;  Rm 54-1424;  77 Massachusetts Ave.
             Cambridge, MA 02139-4307
emails:  eh3 at mit.edu                ed at eh3.com
URLs:    http://web.mit.edu/eh3/    http://eh3.com/
phone:   617-253-0098
fax:     617-253-4464