DESCRIPTION

Introduction

Melissa is a bunch of machines dedicated to interactive analysis tasks and program testing. There is so fare no batch queue on this machines. It is also not a real cluster in the sense that there is no front machine dedicated to the user connection and a list of hidden nodes. Each user can connect to any of the Melissa machines. A tool (called rfm) has been developed to launch connections and utilities on the less loaded Melissa node.

 

Melissa the actual status

• Actually Melissa is made of 12 DELL Optiplex GI 280 (P4 at 2.8 GHz) mono-processor machines having 1 GB of memory and 40 GB of disk space. The machine names go from daplxa221 to daplxa232.
• The current operating system is Scientific Linux 3.0.3.
• Each machine has a scratch disk of 30 GB named from scratch01 to scratch12 which are auto mounted to all the machines. This disk space is neither automatically cleaned nor backuped which means that it is up the user to take care of it.
• The Melissa machines are interconnected via a 1Gb/s network.

 

Setting your environment

Right now the only official users of Melissa are ATLAS members. There for all usefully software have been installed on the ATLAS group disk. In future it is planed to install them on a special disk area dedicated only to the Melissa users. To use the Melissa software you need to add the following stuff into you .login file:

set SYS_NAME=`/home/usr201/mnt/jpmeyer/bin/unamex`
set MACHNUM = `uname -n | awk '{print substr($0,7,9)}'`
if ( $SYS_NAME == 'Linux' ) then
if ( ($MACHNUM > 220 && $MACHNUM < 233) ) then
#
# ........ group disk
#
setenv ATLAS /home/manip/mnt/atlas
#
# ........ cernlib
#
setenv CERN /home/manip/mnt/atlas/jpmeyer/install/melissa/cern
setenv CERN_LEVEL pro
setenv CERNINC $CERN/$CERN_LEVEL/include
setenv CERNBIN $CERN/$CERN_LEVEL/bin
setenv GEANTSRC $CERN/$CERN_LEVEL/include
setenv GEANTINC $CERNINC/geant321
setenv CERN_LIBS "-lpacklib-shift -lmathlib -lshift -L/usr/local/lib"
setenv CERNLIB "-L$CERN/$CERN_LEVEL/lib $CERN_LIBS"
#
# ........ root 4.0.2.00 disponible en local
#
#setenv ROOTSYS /usr/local/root/root_v4.02.00
#
# ......... ou root 4.03.04 disponible sur le disque de groupe
#
setenv ROOTSYS /home/manip/mnt/atlas/jpmeyer/install/melissa/root/root_v4.04.02
#
setenv PATH $HOME/.rfm/bin:${ROOTSYS}/bin:${ATLAS}/bin:${PATH}
#
# ........ ld library path
#
setenv LD_LIBRARY_PATH ${ROOTSYS}/lib:${CERN}/pro/lib
echo "login on melissa"
endif
endif

Connecting to Melissa

In order to connect to melissa you can use either ssh, rsh, xon or rlogin depending from where you are doing it. If you stay outside the center (for example at CERN) you need first to connect to the daplxa cluster using the following command:

ssh -X daplxa.saclay.cea.fr

From there you can connect to the Melissa machines by any of the previously mentionned tools or use the rfm tool to choose the less loaded node.

rfm xterm

or

ssh -X daplxa232.saclay.cea.fr

or

xon daplxa232.saclay.cea.fr