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scratch.txt

Guest on 26th April 2022 10:05:32 AM

  1. :orphan:
  2.  
  3.  
  4. The scratch directory is the place where DIRAC will write temporary files. At
  5. the beginning of the run, DIRAC copies input files and the binary into the
  6. scratch space and at the end of the calculation, the output is copied back,
  7. possibly together with other useful (restart) files.
  8.  
  9.  
  10. How you can set the scratch directory
  11. =====================================
  12.  
  13. You can set the scratch space like this::
  14.  
  15.   $ pam --scratch=/somepath
  16.  
  17. If ``--scratch`` is not set, DIRAC will look for the environment variabls
  18. ``DIRAC_TMPDIR``.
  19.  
  20. If these variables are not set, DIRAC defaults to
  21. ``$HOME/DIRAC_scratch_directory``.
  22.  
  23. On your local computer you typically want to use the same scratch space every
  24. time and you may be tired of typing ``pam --scratch`` every time.  In this
  25. case, put ``--scratch=/somepath`` in your ``~/.diracrc`` or export
  26. ``DIRAC_TMPDIR`` in your ``~/.bashrc`` or equivalent.
  27.  
  28. DIRAC will always append ``$USER/DIRAC_inp_mol_pid`` to the scratch path.  This
  29. is to prevent users from accidentally wiping out their home directory.
  30.  
  31.  
  32. What if you don't want DIRAC to append anything to your scratch path
  33. ====================================================================
  34.  
  35. For this use::
  36.  
  37.   $ pam --scratchfull=/somepath
  38.  
  39. In this case DIRAC will use the path as it is and not append anything to it.
  40. Be careful with this since DIRAC may remove the path after the calculation
  41. has finished.
  42.  
  43.  
  44. How to set the scratch path on a cluster
  45. ========================================
  46.  
  47. On a cluster you typically want to be able to find the scratch directory based
  48. on some job id. If you are on a cluster with a Torque/PBS scheduler then it can
  49. be useful to set::
  50.  
  51.   $ pam --scratch=/somepath/$USER/$PBS_JOBID
  52.  
  53.  
  54. Cluster with a global scratch disk
  55. ----------------------------------
  56.  
  57. This means that all nodes write temporary files to the same disk.
  58.  
  59. No additional flags are needed for this run.
  60.  
  61.  
  62. Cluster with local scratch disks
  63. --------------------------------
  64.  
  65. This means that each node writes temporary files to its own disk.
  66.  
  67. For this situation the input files have to be distributed over
  68. the nodes based on ``--machfile``::
  69.  
  70.   $ pam --scratch=/somepath/$USER/$PBS_JOBID --machfile=/path/to/machfile
  71.  
  72. If you don't give ``--machfile``, DIRAC assumes that you run using a global
  73. scratch disk.
  74.  
  75. The list of machines is typically generated when the scheduler launches
  76. the job but you can also set the list of machines manually.
  77.  
  78. The input files are by default distributed using rsh/rcp. If your cluster
  79. does not support these you can change to ssh/scp protocol::
  80.  
  81.   $ pam --scratch=/somepath/$USER/$PBS_JOBID --machfile=/path/to/machfile --rsh=ssh --rcp=scp

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