Joint Workshop September 2023 - Parallel I/O

Talk held by Gregor Weiß, HLRS about Parallel I/O in OpenFOAM. A revised parallel I/O method is being developed, implemented and tested. Target is an I/O strategy, which will fully elaborate the performance of the underlying I/O system with parallel access to data independently from the number of MPI-processes and number of used cores, removing major scalability and usability bottlenecks. The new I/O is implemented natively in OpenFOAM based on ADIOS2. In contrast to the current I/O strategy, the number of files and mesh/field decomposition/reconstruction/redistribution steps are substantially reduced and the user can still efficiently make changes to already decomposed cases.