Speaker
Description
German computing sites play a vital role in the Large Hadron Collider (LHC) job processing and data storage as part of the Worldwide LHC Computing Grid (WLCG). The storage and computing contributions of university-based Tier-2 centres in Germany are transitioning to the Helmholtz Centres and National High Performance Computing (NHR) sites, respectively, to meet the growing data and computational demands of the High-Luminosity LHC (HL-LHC). This transition requires scalable strategies for data storage, data distribution, and their integration with computing centres. Research towards this transition is conducted in Goettingen, where both the Tier-2 WLCG centre GoeGrid and the NHR HPC cluster Emmy are located. The GoeGrid batch system is extended with containers, allowing Emmy nodes to act as virtual worker nodes for LHC job processing. Since large local mass storage is not planned at NHR centres for WLCG operations, alternative storage stolutions are being evaluated. Two promising approaches are being tested: pre-caching with a small storage instance of the order of 100 terabytes at GoeGrid, and direct data access via WAN to the Helmholtz Centres DESY and GridKa. Their performance have been benchmarked on Emmy using the current WLCG workflow management system. While results are promising, ongoing studies are exploring potential bottlenecks to enable scalability and applicability at other computing centres without large local storage. The concepts, performance results, and limitations of these approaches are presented, offering insights into future LHC computing.