Compressing model log files

[blimlim]

Model log files can take up a significant amount of storage. For a single year of ESM1.5 simulation, the sub-models produce:

• Atmosphere: ~50M
• Ocean: ~60M
• Ice: ~900M
  which can add up over long simulations.

Previous discussions raised the idea of compressing the log files during the archive step. @aidanheerdegen mentioned a good place to start would be the CICE driver, and if successful it could be expanded to a general (perhaps optional) step across models.

A couple of implementation questions/concerns:

• Would it be preferable to compress each log file separately, or combine all the logs for a single sub-model into a tar.gz?
• People may have workflows set up for extracting information from the logs (e.g. subroutine timing information) which would be affected.

[aidanheerdegen]

It is possible to grep into a compressed tar archive file:

$ ls
cice_in.nml    ice_diag.d    iceout085  iceout087  iceout089  iceout091  iceout093  iceout095  input_ice.nml                                      
debug.root.03  ice_diag_out  iceout086  iceout088  iceout090  iceout092  iceout094  iceout096
$ grep 'Timer  15:  from_ocn' *
ice_diag.d:Timer  15:  from_ocn       7.83 seconds
$ tar -zcvf logs.tar.gz *
cice_in.nml
debug.root.03
ice_diag.d
ice_diag_out
iceout085
iceout086
iceout087
iceout088
iceout089
iceout090
iceout091
iceout092
iceout093
iceout094
iceout095
iceout096
input_ice.nml
$ zgrep -a 'Timer  15:  from_ocn' logs.tar.gz                                                                           
Timer  15:  from_ocn       7.83 seconds

So I think a compressed tar archive makes most sense.

The question of what to archive? Probably best to have a list in the model driver of patterns to match files. Simple case would be just anything that beginswith a list of strings.

For cice5 it would be

log_files = ['iceout', 'ice_diag', 'debug.root']

Which isn't too bad.

For mom5 (in ESM1.5)

log_files = ['fort', 'logfile', 'debug.root', 'oceout']

For atmosphere (in ESM1.5)

log_files = ['atm.fort', 'fort', 'nout', 'debug.root']

Are the various hist files also log files? (xhist, thist, ihist)