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On earlier NYU HPC clusters, the output of batch jobs appeared as it happened, in a file like "my_job.o12345" in the job submission directory. When jobs are submitted from /scratch, this can causes a heavy small-block-I/O load on the Lustre filesystem, which impacts /scratch performance.

On Mercer, job stdout and stderr are instead written to hidden files in your $HOME area, under $HOME/.pbs_spool. When the job completes, the my_job.o12345 and my_job.e12345 files are moved to their final location.

You can monitor your job's progress by looking for its output in this hidden directory

If your job writes too much to stdout or stderr, these temporary files might (temporarily) fill up your $HOME space allocation. If this is occurring, first check if you can reduce the amount of stdout and stderr (they can slow down your program, contact us if you would like assistance with this). Another option is to redirect stdout and stderr to a file in some other location:

  • With bash:

my_program > my_output_file 2>&1

 

  • With csh/tcsh

my_program >& my_output_file


Options to manage job output:

  • -N jobname
    Give the job a name. The default is the filename of the job script. Within the job, $PBS_JOBNAME expands to the job name 
  • -j oe
    Merge stderr into the stdout file 
  • -o path/for/stdout
    Send stdout to path/for/stdout. Can be a filename or an existing directory. The default filename is $PBS_JOBNAME.o${PBS_JOBID/.*}, eg myjob.o12345, in the directory from which the job was submitted 
  • -e path/for/stderr
    Send stderr to path/for/stderr. Same usage as for stdout.
  • -M my_email_address@nyu.edu
    Send email to my_email_address@nyu.edu when certain events occur. By default an email is sent only if the job is killed by the batch system.
  • -m b -m e -m a -m abe
    Send email when the job begins (b), ends (e) and/or is aborted (a).  

Options to set the job environment:

  • -S /path/to/shell
    Use the shell at /path/to/shell to interpret the script. Default is your login shell, which at NYU HPC is normally /bin/bash
  • -v VAR1,VAR2="some value",VAR3
    Pass variables to the job, either with a specific value (the VAR= form) or from the submitting environment (without "=")  
  • -V
    Pass the full environment the job was submitted from

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