Changes to this message: MPP cluster user operation delayed LRZ intends to take two new systems into user operation in its Linux Cluster infrastructure within the next weeks; these new systems are focused on efficient execution of large scale parallel programs. The first system is an Infiniband-connected cluster of 16-way shared memory systems with more than 2500 cores delivered by MEGWare, and the second one consists of SGI Ultraviolet (UV) large-scale shared memory systems with more than 2000 cores in total. It is expected that the Infiniband cluster will become available for regular user operation first, followed by the UV system somewhat later. However, the existing UV will be retired from user operation soon because the space it presently occupies will be needed for the new system. Furthermore, the Infiniband cluster will need to be moved into the new LRZ infrastructure later in summer, so there will be a prolonged interruption of operation some weeks after its initial user operation. The altix2 system will be retired from user operation once the new systems are fully available. Users are advised that all new systems, which are targeted to running large parallel jobs, will use SLURM as a batch scheduler. Existing SGE scripts will not work on the new clusters - they will require rewriting of the control section, and will also need modification of the program startup procedure in the script section. Documentation for the new batch system will be available via the Linux Cluster page (http:// www.lrz.de/services/compute/linux-cluster) once user operation starts. The usage instructions for startup of MPI programs will also be updated. We hope that this capacity upgrade will reduce the rather long waiting times which nowadays are observed for parallel jobs. We intend to keep you informed about the status of these new systems via updates to this document. ----------------------------------------------------------------------- Timeline for operational changes Friday, August 12 The Ultraviolet system uv1 has an interruption of services for 2 hours, starting at 10:00. All running jobs will be removed from the system. The reason for this is that the machine must be physically moved to make room for the UV upgrade. Thursday, August 18 The Infiniband cluster is opened for general user operation. Update: General user operation is delayed from the original target date, probably until Thursday, because an unforeseen problem with the batch system has surfaced when switching on accounting. Monday, September 12 The Altix 4700 is retired from user operation. This information is also available on our web server http://www.lrz-muenchen.de/services/compute/aktuell/ali4065/ Reinhold Bader