Faq t2b

List of the UIs / mX machines:

- m0 , m1 , m2 , m3 => 20 minutes of CPU time per process
- m5 , m6 , m7 , m8 , m9 => 5 hours of CPU time per process

Keep ssh connection to UI open:

Add option ' -o ServerAliveInterval=100 ' to your ssh command

Send a job to the local cluster:

qsub -q localgrid -o script.stdout -e script.stderr [-l walltime=<HH:MM:SS>] myscript.sh

MadGraph taking all the cores of a workernode

The default settings for MadGraph is to take all the available cores. This kills the site. If the number of cores used by MadGraph is higher than 1, this needs to be asked to the job scheduler with the following directive added to qsub:

 -lnodes=1:ppn=2 

Where ppn is the number of cores you request.
To tell MadGraph the number of cores he can take per job, use the following recipe:

./bin/mg5_aMC 
set nb_core 1  #or 2 or whatever you want
save options

Note 'nb_core' and 'ppn' must alway be the same value!
Note also that if you ask for more than one core your time in the queue will probably be longer as the scheduler needs to find the correct amount of free slots on one single machine. We advise against putting this number higher than one unless you really need it for parallel jobs.

Access internet faster from the UIs

Since our bandwidth with internet is limited and extremely expensive, you need to use the another one:

• For http/https traffic (uses the university traffic)

export http_proxy=http://qproxy.wn.iihe.ac.be:3128
export https_proxy=http://qproxy.wn.iihe.ac.be:3128

• For ssh traffic, through a server you have access to (example using CERN)

edit your .ssh/config file ===>

host github.com
    ProxyCommand ssh MYUSERNAME@lxplus.cern.ch nc github.com 22
    User MYUSERNAME