During the last two weeks of September 2011 (09/19 - 09/30), the HPC will have its yearly upgrade. During this period, we will perform a major upgrade of the operating system on our compute nodes, login nodes and interactive cluster: we will switch from CentOS 5.4 to Red Hat Enterprise Linux (RHEL) 6.1. This switch was necessary since the Linux kernel in centos does not fully support some our newer hardware. The transition to RHEL 6.1 has a number of implications for users of our cluster and they are described in this document.

Libraries

Almost all system libraries (glibc, jpeg, etc) will be upgraded, which means that we had to recompile all our software libraries too (for example all our mpi variants and libraries like netcdf). This means that if you have compiled software, you will have to recompile it. If you get errors like "library not found" type of errors, you will need to recompile your software.

Directory layout

Every linux distribution has it's own standard directory layout. If you use our profile.d scripts, you will not be affected by the new paths of programs. However, if you put the paths of program in your scripts (for example, /usr/mpi/gnu/openmpi/bin/mpirun), you might want to read our new paths and layout pages.

New compilers and mpi version

To avoid to many changes, we tried to avoid to many extreme version changes. Unfortunately, that was not always possible. On our new software versions pages, new versions of our compilers and mpi versions are described. In almost all cases, you will need to recompile your software if you use MPI.