CCNU LHCb farm 2

Computers

The computers for LHCb are comput19-23. CVMFS is installed on these machines.

Softwares

ROOT

The simplest way to set up root is by running

source /home/lhcb/setups/setup_root.sh

It will set up ROOT from LCG on CVMFS. Currently, the version of root in this script is 6.18.04 with python 3 support. One can also set up a different version in a similar way. For example, if one needs 6.18.00 with python 2, this command will do it:

source /cvmfs/sft.cern.ch/lcg/releases/LCG_96/ROOT/6.18.00/x86_64-centos7-gcc8-opt/ROOT-env.sh

aspell

aspell is installed on comput19 and comput23

slurm jobs

中文教程

An example script for batch job submission can be found in the attachment and this command could be used to submit jobs:

sbatch test_job.sh

Note that the options are given inside the script.

Useful webpages farm_slurm_commands Slurm Tutorial

Problems and solutions

Auto logout from comput19

comput19 is configured to auto logout inactive users by setting TMOUT=3600. One can keep some jobs running in screen by setting TMOUT= there. (TMOUT variable is readonly in the login session but could be overwritten inside a screen session). One can also put these lines inside .bashrc to overwrite the variable automatically in any screen sessions:

if [ "$STY" != "" ]; then ## check if this is a screen session
   export TMOUT=
fi

Direct-access farm2 from hepfarm

We could use sshfs to mount part of the space in farm2 to hepfarm. This is not in place yet. We will only do this if it's considered useful.

1. mount/unmout need root permission
2. Need to set up a file to map the users
3. If we want to set up this, we could use the lhcb account and just mount a subdirectory in its home

Links

CcnuTeaching CCNULHCbFarm

-- DongliangZhang - 2020-02-21