Rewriting application I/O for performance and scalability on petaflops machines easily becomes a formidable task in terms of man-hour effort. Furthermore, on HPC systems the gap of compute to I/O capability in Tflop/s vs GByte/s has increased by a factor of 10 in recent years. It makes the insertion of I/O forwarding software layers between the application and file system layer increasingly feasible from a performance point of view. This whitepaper describes the work on evaluating the IOFSL I/O

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... Forwarding and Scalability Layer on PRACE applications. The results show that the approach is relevant, but is presently made infeasible by the associated overhead and issues with the software stack.