Batch Jobs On Lxplus

Contents

• Login to Lxplus
• Batch Script
• Job Submission
• Checking Job Status
• Killing a Job
• Submitting Multiple Batch Jobs
• Links

Login to Lxplus

On lxplus you are limmited both in disk space and CPU time. In order to run medium to large size jobs from lxplus, you will need to submit a batch job using bsub. Your job will be submitted to a machine compatible with the machine you are submitting from, so for CMSSW_1_3_X and lower

ssh username@lxslc3.cern.ch

and for CMSSW_1_4_X and higher

ssh username@lxplus.cern.ch

Batch Job Script

Copy the following script into a file (say lxplusbatchscript.csh) and edit the file to run on your .cfg file. Also edit the last line to write into your CASTOR area (you have limited space on lxplus. If you don't use CASTOR you may lose your output!).

# Lxplus Batch Job Script
set CMSSW_PROJECT_SRC="cmssw_projects/13X/cmssw131hlt6/src"
set CFG_FILE="cfgs/steps2_3_4_5.cfg"
set OUTPUT_FILE="Analyzer_Output.root"
set TOP="$PWD"

cd /afs/cern.ch/user/s/ssimon/$CMSSW_PROJECT_SRC
eval `scramv1 runtime -csh`
cd $TOP
cmsRun /afs/cern.ch/user/s/ssimon/$CMSSW_PROJECT_SRC/$CFG_FILE
rfcp Analyzer_Output.root /castor/cern.ch/user/s/ssimon/$OUTPUT_FILE

Set the permissions on the script file with

chmod 744 lxplusbatchscript.csh

Job Submission

Now you can submit the job by using bsub, passing it the above script. An example command is

bsub -R "pool>30000" -q 1nw -J job1 < lxplusbatchscript.csh

There are a few arguments specified in this example

• -R "pool>30000" means you want a minimum free space of 30G to run your job.
• -q 1nw means you are submitting to the 1-week que. Other available queues are:
  • 8nm (8 minutes)
  • 1nh (1 hour)
  • 8nh
  • 1nd (1day)
  • 2nd
  • 1nw (1 week)
  • 2nw
• -J job1 sets job1 as your job name.
• < lxplusbatchscript.csh gives your script to the job.

After entering the above command you will get the output

Job <557650> is submitted to queue <1nw>.

The unique job number 557650 is automatically generated.

Checking Job Satus

You can check the status of your job with the command bjobs. (To specify the job use bjobs -J job1 or bjobs 557650)

bjobs

which gives the output

JOBID   USER    STAT  QUEUE      FROM_HOST   EXEC_HOST   JOB_NAME   SUBMIT_TIME
557650  ssimon  PEND  1nw        lxplus096               job1       Aug  9 16:16

You can see that this job is pending. To see more information about pending jobs use bjobs -l, and see man bjobs for more info.

Killing a Job

If you make a mistake and need to kill a job (i.e. submit to wrong queue), you can do so with

bkill jobnumber

To kill all your jobs:

bkill -u username 0

Submitting Multiple Batch Jobs

You can use submitJobs.py.txt script to submit your jobs (right click on it and save it, remove .txt). To use it:

1) Cerate one List.txt file with all the directories for all files you want to run on

For example for local files:

...
file:/afs/cern.ch/.../file_1.root
file:/afs/cern.ch/.../file_1.root
...

or for files in eos:

...
/store/group/.../file_1.root
/store/group/.../file_2.root
...

2) Place the script and the list in the same folder as your script you want it to use and give it permission (chmod 755)

3) Fill the customization area in the submitJobs.py file and run it. You do not need to make any directories, or empty them after the run.

submitJobs.py splits the List.txt file according to numbers you give it (it does not change the file itself). For example if you have 2111 lines in the List.txt file, you can tell it to do 11 jobs per 200 files -- the 11th job will run on 111 files. You do not need to create any directories, it creates tmp directory which contains smaller txt lists and job.sh scripts that are sent with bsub.

After the jobs are done you can see the logs files in tmp folder. This directory is cleared at the start of submitJobs.py script. The result files are created in res directory, which is not cleared. Remember to change the base of the output file name when you submit new jobs. The output files are named according to the string you give in the submitJobs.py script, if you give "outputFile", you will get outputFile_1.root, outputFile_2.root and so on.

Links

• LSF Quick Intro
• Helpful Twiki
• lxbatch page

-- DavidCockerill - 27-Apr-2011