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Batch Scratch

Directories for Batch Jobs
--------------------------

Each machine in the Origin array has a local XFS scratch filesystem.
Each batch job has a per-job scratch directory that is created at the
beginning of the job. This directory is created on the local scratch
filesystem on the host where the job runs, and is based on the batch
JobID and the start time of the job. The name of this directory is 
available to job scripts in the $SCR environment variable.  

For example, job 229106 that started on Feb 5, 1999 at 11:43:22 on 
machine jord1 would have $SCR set to: 

  /scratch-jord1/LSBATCH/229106.5Feb1999114322

The sample batch scripts in /usr/local/doc/lsf/samples illustrate the 
use of $SCR in a batch script.

We strongly advocate use of the msscmd -b/-B options in batch jobs for
guaranteed, automated saving of files. See the msscmd man page and
http://www.ncsa.uiuc.edu/SCD/Hardware/Origin2000/Doc/msscmd.html for
details.

For jobs using the msscmd -b/-B option, after job completion, files are not 
purged from the $SCR filesystem until they are successfully transferred 
or it has been determined that the transfer will never happen (e.g., due 
to user syntax error). For jobs that do not use the msscmd -b/-B option, the 
$SCR directory will be purged immediately after job completion.

For jobs using the msscmd -b/-B option, email is sent to the user once 
the transfer requests to mass storage are processed by the system. Users 
are not notified in email when files are purged from the $SCR directory.

We strongly recommend using the machine-local scratch directory ($SCR) for
running batch jobs rather than NFS mounted non-local disk (e.g.,
scratch-modi4) for performance and reliability reasons. Note that use
of home directories for batch jobs is also limited by the quota there.
Use of non-local disk is at your own risk. No refunds will be issued for
batch jobs that fail due to use of non-local disk.

The following two utilities are useful for monitoring currently running
jobs:

1. cdjob [jobid]

changes the working directory to the scratch directory of a running batch 
job. If the jobid is not specified, you must have only one running job.

2. bjobdir [bjobs options]

outputs the scratch directory name for each job specified. 

Note that access to all batch machine scratch filesystems from any other 
machine is read only. /scratch-modi4 is both read and write accessible from 
the batch scratch filesystems. Backups are not performed on the
scratch filesystems.

Please contact the NCSA Consulting Office via e-mail at consult@ncsa.uiuc.edu 
or by telephone at (217) 244-1144 with any questions or problems.
Silicon Graphics Origin2000:usr/news/Batch_Scratch
Last Modified: January 11, 2000